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Keywords:

  • acne;
  • acne treatment;
  • herbal cosmetics;
  • herbs;
  • topical applications

Synopsis

  1. Top of page
  2. SynopsisRésumé
  3. Introduction
  4. Sebaceous glands in acne formation
  5. Propionibacterium acnes in acne formation
  6. Reactive oxygen species in acne formation
  7. Active ingredients for topical acne treatment
  8. Herbs for acne treatment
  9. Discussion
  10. Conclusion
  11. Acknowledgement
  12. References

Acne vulgaris suppresses an individual’s self-confidence by causing distress with regard to physical appearance, which affects a significant number of individuals during puberty and is delineated by adolescence. Several treatments have been introduced to decrease the aesthetic and psychological problems caused by acne. The topical application of therapeutic agents has been found to be more feasible than hormonal treatment and laser therapy. The ingredients in topical acne treatments, particularly herbs and naturally derived compounds, have received considerable interest as they have fewer adverse effects than synthetic agents.

Résumé

L’acné vulgaire touche à l’assurance d’un individu en causant une détresse face à son apparence physique. Elle affecte un nombre important d’individus pendant la puberté et est associée à l’adolescence. Plusieurs traitements ont été proposés pour diminuer les problèmes esthétiques et psychologiques causés par l’acné. L’application topique d’agents thérapeutiques a été estimée plus aisée qu’un traitement hormonal et une thérapie laser. Les ingrédients des traitements topiques de l’acné, particulièrement les plantes et les composés naturels dérivés ont suscité un intérêt considérable par leurs moindres effets indésirables que les ingrédients synthétiques.


Introduction

  1. Top of page
  2. SynopsisRésumé
  3. Introduction
  4. Sebaceous glands in acne formation
  5. Propionibacterium acnes in acne formation
  6. Reactive oxygen species in acne formation
  7. Active ingredients for topical acne treatment
  8. Herbs for acne treatment
  9. Discussion
  10. Conclusion
  11. Acknowledgement
  12. References

Acne is a skin disorder that suppresses an individual’s self-esteem with regard to physical appearance and has a clinical onset during puberty and adolescence [1]. A high incidence of acne is found in girls aged 14–17 and in boys aged 16–19 [2]. The pathogenesis of acne is regulated by sebum hypersecretion in deformed follicles, which leads to microcomedones, and the follicular hyperproliferation of microcomedones causes inflammation [3], and comedones [4] in both open and closed types (black and white comedones) appearing in papules, pustules, nodules and cysts [5]. The resulting skin condition with sebum enrichment is prone to the anaerobic growth of Propionibacterium acnes, which is the main causative microorganism in acne. In addition, Staphylococcus epidermidis and Pitryosporum ovale are present in acne lesions [6]. Proliferation of these microorganisms, mainly P. acnes, leads to inflammatory lesions and severe acne.

Therefore, acne formation needs to be addressed, particularly acne vulgaris. In addition to adolescent acne, drugs are a relatively common cause of eruptions resembling acne. Drug-induced acne or acneiform dermatoses that can have a sudden onset e.g. within 1 day of drug administration can be resolved after the drug is stopped. Acneiform dermatoses have an unusual lesion distribution, such as inflammatory papules and pustules that are small and uniform in size (monomorphic), and can lead to secondary comedones of which the earliest histological event is spongiosis followed by lymphocytic and neutrophilic infiltrates, respectively [7]. Those drugs capable of producing eruptions have been summarized elsewhere [8]. Therefore, although the initial causes are different, the pathogenesis of acne vulgaris can be similar. Thus, some treatments are used for both adolescent and drug-induced acne. In this review, the therapeutic ingredients in topical applications relevant to the pathogenesis of acne vulgaris lesions were evaluated, as topical application is more feasible [9], especially with the naturally derived compounds already in use and candidate compounds.

Sebaceous glands in acne formation

  1. Top of page
  2. SynopsisRésumé
  3. Introduction
  4. Sebaceous glands in acne formation
  5. Propionibacterium acnes in acne formation
  6. Reactive oxygen species in acne formation
  7. Active ingredients for topical acne treatment
  8. Herbs for acne treatment
  9. Discussion
  10. Conclusion
  11. Acknowledgement
  12. References

Acne is pronounced in puberty and adolescence [10] and is positively related to sebaceous gland function, particularly in teenage boys [11], which androgenically stimulates higher sebum secretion [12]. The secreted sebum normally contains a mixture of lipids, squalene, wax and cholesterol both in free and in ester forms and triglycerides that naturally provide a skin barrier function [13]. However, the resulting abnormalities in sebaceous glands because of hormonal effects alter sebum composition and linoleic acid content is notably decreased [14]. Thus, the skin barrier is impaired and colonization of normal flora is promoted.

Propionibacterium acnes in acne formation

  1. Top of page
  2. SynopsisRésumé
  3. Introduction
  4. Sebaceous glands in acne formation
  5. Propionibacterium acnes in acne formation
  6. Reactive oxygen species in acne formation
  7. Active ingredients for topical acne treatment
  8. Herbs for acne treatment
  9. Discussion
  10. Conclusion
  11. Acknowledgement
  12. References

Abnormalities in sebaceous gland function, particularly water-soluble lipids mainly facial triglycerides in sebum, are inflammatory-enhancing factors that promote the metabolism of the normal flora, such as P. acne. P. acne has a mitogenic effect towards T cells [15] by means of heat-shock proteins (HSPs) [16], contributes to toll-like receptors (TLRs) [17] and activates CD4+ expressed in keratinocytes and sebocytes and neutrophil function [18]. Colonization of this anaerobe consequently produces cytokines and other proinflammatory compounds including interleukins (IL), tumour necrosis factors (TNF), interferon (IFN) gamma and granulocyte–macrophage colony-stimulating factor (GM-CSF) [5, 19]. In addition to follicular keratinocytes, IL induction leads to microcomedone formation, and the bacterium activates TLRs inducing the attraction of lymphocytes, neutrophils and macrophages. Abnormal keratinization and deficiency of linoleic acid in the follicle also promote the growth of P. acne [20], which in turn stimulates the production of proinflammatory cytokines/chemokines in sebocytes [21] and provokes chronic inflammatory lesions [22].

Reactive oxygen species in acne formation

  1. Top of page
  2. SynopsisRésumé
  3. Introduction
  4. Sebaceous glands in acne formation
  5. Propionibacterium acnes in acne formation
  6. Reactive oxygen species in acne formation
  7. Active ingredients for topical acne treatment
  8. Herbs for acne treatment
  9. Discussion
  10. Conclusion
  11. Acknowledgement
  12. References

Reactive oxygen species (ROS) are subsequently generated from the hypercolonization of P. acnes [5, 23] in addition to metabolism in living organisms and from UV exposure. Although ROS perform a useful function in the skin barrier against acne microbes [24, 25], excess formation affects skin condition by activating neutrophil infiltration. ROS including singlet oxygen, superoxide anion, hydroxyl radical, hydrogen peroxide, lipid peroxide and nitric oxide (NO) play an important role in inflammatory acne as well as in tissue injury. ROS stimulate the formation of nuclear factor κB (NF-κB) [26], promote TNF formation [27] and consequently activate T lymphocytes and keratinocytes. The cytokines IL, TNF, IFN, lipopolysaccharide (LPS), transforming growth factor (TGF) and prostaglandin (PG) are then produced and released [28–32].

In summary, skin inflammation is initiated by CD4+ in T lymphocytes, regulated by TLRs following neutrophil infiltration which generates ROS, and protease enzymes leading to follicular wall rupture of sebaceous glands. This consequently changes the composition of sebum, particularly linoleic acid. Hyperkeratinization is initiated as well as a reduction in desquamation. Subsequently, the proinflammatory cytokines, NF-κB, IL, TNF, IFN, LPS, TGF, PG and GM-CSF are released causing microcomedones. The resulting microcomedones further develop into comedones and inflammatory lesions.

The topical agents used in the treatment of acne have been summarized, particularly the naturally derived compounds as they are believed to be safer than the synthetic compounds [33]. In addition, P. acne resistance to some antibiotics used in the treatment of acne has been observed [34, 35].

Active ingredients for topical acne treatment

  1. Top of page
  2. SynopsisRésumé
  3. Introduction
  4. Sebaceous glands in acne formation
  5. Propionibacterium acnes in acne formation
  6. Reactive oxygen species in acne formation
  7. Active ingredients for topical acne treatment
  8. Herbs for acne treatment
  9. Discussion
  10. Conclusion
  11. Acknowledgement
  12. References

Retinoic acid and derivatives

Keratolytic agents such as cis-retinoic acid, retinol and retinol ester are commonly used to normalize keratinization as they have a suppressive effect on sebaceous gland function [9, 36, 37]. These vitamin A derivatives suppress TLR’s expression and inhibit IL and IFN production. Cell migration of CD4+ and CD8+ T lymphocytes and macrophage is inhibited [38, 39]. Tretinoin or trans-retinoic acid is also used as a comedolytic agent. It normalizes follicular epithelium desquamation by unplugging the follicle. The growth of P. acnes is reduced consequently. However, topical application of anti-inflammatory retinoids [40] leads to irritation, which is dose responsive [41]. Therefore, appropriate vehicles should be used to diminish this effect in addition to structural modification. Adapalene, a retinoid-like activity agent, with comedolytic and anti-inflammatory effects was synthesized. It has been formulated mainly in a gel and cream that found more effective than tretinoin [42]. Another retinoid-like activity agent, tazarotene, which is rapidly converted to its active form, tazarotenic acid, has been introduced. However, it had a greater effect on non-inflammatory than on inflammatory lesions, which was dose dependent [43] as reviewed [44] with the other retinoid derivatives such as motretinide, retinoyl β-glucuronide and retinaldehyde. Unfortunately, there is no comparative study with tretinoin.

Benzoyl peroxide

The application of benzoyl peroxide, an anti-microbial agent with high affinity that inhibits P. acnes and S. aureus [36], was incorporated into various formulations, mainly gels [45]. Benzoyl peroxide improves inflammatory and non-inflammatory lesions [46] by generating ROS in the sebaceous follicle-inhibiting microorganisms [24, 25] with a reduction in free fatty acids triggering the formation of microcomedones [47]. However, its irritancy limits its application [48]. Combination products were, therefore, formulated to overcome this drawback with an additional benefit on the synergistic effect when in combination with adapalene [49].

A comparative study between the combination of erythromycin and benzoyl peroxide and the combination of erythromycin and tretinoin was conducted. The former combination significantly improved the treatment of acne vulgaris [50].

Salicylic acid

Salicylic acid, a mild keratolytic and anti-inflammatory agent [51] that inhibits PG synthesis, was used to remove follicular clog [36] in various formulations, particularly an alcoholic solution for cleansing. This formulation posed better efficacy than benzoyl peroxide [52]. Salicylic acid is a milder agent compared with retinoids. A combination of salicylic acid, and benzoyl peroxide would increase treatment efficacy as their mechanisms are differ [45]. In addition to being a cleansing product, skin peeling using salicylic acid was found to significantly reduce comedones [53].

Azelaic acid

Naturally occurring azelaic acids possess comedolytic activity [54], anti-bacterial properties against P. acnes [55] including the normalization of keratinization [56] and anti-inflammatory effects on neutrophil function [57] as well as skin-lightening properties [58]. In addition to a single treatment with azelaic acid, combination treatments with other anti-acne agents, particularly benzoyl peroxide, enhanced efficacy [59]. Furthermore, azelaic acid is safer with less irritation and phototoxic response [60]. In addition, P. acne resistance to azelaic acid has not been reported [56].

Vitamin B

Similar to vitamin A that is extensively used in acne, vitamin B3 or nicotinamide is useful as it inhibits IL-8 production in keratinocytes through NF-κB induced by P. acnes during the early phase of inflammation [61]. Consequently, melanosomes transferring to keratinocytes are reduced [62]. In addition, nicotinamide was believed to suppress leucocyte peroxidase that damaged skin barrier function including enhancing sebum synthesis and consequently reducing transepidermal water loss. Therefore, it was regarded as the newest vitamin for inflammatory lesion treatment.

Vitamin C

Ascorbic acid or vitamin C, the most well known anti-oxidant, poses anti-inflammatory properties that are appraisal in the treatment of acne [63]. It scavenges the generated radicals terminating inflammation accordingly. However, it is unstable in a free form. Therefore, structural modification, for example sodium ascorbyl phosphate achieving stability, was carried out. This more stable derivative was used to treat the inflammatory lesions in addition to retinol. The combination treatment significantly reduced the lesions [9].

Serum zinc level was found to be low in patients with acne [64]. Treatment with zinc was therefore shown to improve inflammatory acne [65].

In addition, oral and topical antibiotics have been used in the treatment of acne. This article will briefly discuss only macrolides and tetracyclines, which are the main antibiotics used for acne, as informative reviews have been presented [34, 66–68].

Macrolides

In addition to the aforementioned active agents, topical administration of antibiotics particularly macrolides are used in the treatment of acne. Oral administration is used for severe acne and acne that is resistant to topical treatment [1]. The macrolides, erythromycin and clindamycin, are used with respect to their anti-oxidant and anti-inflammatory activities [69, 70]. However, P. acne resistance [35] as well as gastrointestinal irritation and vaginal candidiasis especially photosensitivity including drug interactions were found following applications of macrolides [66]. Although a structural modification in a fewer gastrointestinal side-effect agent, azithromycin, was carried out. It was found to accumulate in breast milk [71].

Tetracyclines

Another class of antibiotic that is widely used in acne treatment is tetracyclines. Tetracyclines show anti-inflammatory activity inhibiting PG synthesis as well as NO synthase suppression [72, 73]. However, the adverse effects of tetracyclines are similar to those of macrolides. The most common side effects are lightheadedness, dizziness and tinnitus [74] including yellow staining of teeth and nail diseases such as photo-onycholysis, although these side effects are not common in doxycycline and minocycline. Light sensitivity has been demonstrated following the administration of doxycycline [75].

To overcome the adverse effects of antibiotics, combination therapy with a systemic treatment should be conducted. Stepwise treatment must be carried out to minimize antibiotic exposure diminishing microbial resistance.

In addition to the aforementioned treatments, hormonal therapy with anti-androgens such as spironolactone, flutamine and cyproterone acetate has been used to treat acne. However, adverse effects have been noted [10, 76]. Laser and light-based therapy potentially clear acne with improvements in acne scarring and skin texture. Nonetheless, these methods are costly and pain causing [77].

Thus, a natural therapy lacking adverse effects is highly desired with respect to its conceivable safety [33] and rare P. acne resistance. Naturally derived compounds, particularly those from herbs, are therefore reviewed in this article. The herbs included are those of well known and candidate herbs used in the future development of anti-acne products.

Herbs for acne treatment

  1. Top of page
  2. SynopsisRésumé
  3. Introduction
  4. Sebaceous glands in acne formation
  5. Propionibacterium acnes in acne formation
  6. Reactive oxygen species in acne formation
  7. Active ingredients for topical acne treatment
  8. Herbs for acne treatment
  9. Discussion
  10. Conclusion
  11. Acknowledgement
  12. References

The use of natural remedies is a highly approached in human health [78], in particular cosmetics with an ongoing search for novel biologically active botanical agents [79]. Traditional therapeutics, for instance ayurvedic formulations [80], which are sometimes classified as complementary and alternative medicine (CAM), have been used in acne treatment. Therefore, plants that are currently used and those with a high potential are summarized as follows:

Already used herbs

Aloe vera extract is used as a component in Ayurvedic formulations. It significantly reduced acne lesions [80]. This Asian dermatological remedy was in accord with the therapeutic use of Aloe spp. in South Africa [81]. However, A. vera was insignificant to suppress P. acnes-induced ROS and proinflammatory cytokines [82]. In the same ayurvedic formulation, Azadirachta indica, Curcuma longa and Hemidesmus incidus were used for acne treatment [80]. These herbs significantly suppressed the production of ROS induced by P. acnes [82]. Accordingly, their anti-inflammatory activity should be stronger than A. vera, highlighting their potential in inflammatory lesions treatment.

A common spice, poultice onion (Allium cepa), was traditionally used for acne [83] owing to its mild keratolytic, anti-fungal and bacteriostatic properties with respect to its sulphur containing [84] including its anti-inflammatory flavonoids [85]. However, its malodor limits the application as well as the possibility of irritation.

Asia is not the only continent using traditional herbs for the treatment of acne vulgaris. Centella asiatica was used as a general tonic for leprosy and wounds particularly for acne in Africa [86]. Although its mechanism remains unknown, skin care products containing C. asiatica are widely commercialized in Asia.

Essential oils of Eucalyptus radiate and Melaleuca alternifolia commonly known as Australian eucalyptus and tea tree, respectively, have been extensively used in acne treatment [87]. M. alternifolia oil gel was found to effectively reduce acne lesions compared with benzoyl peroxide at the same concentration but fewer side effects [88]. Its inhibitory activity against skin flora including S. aureus, S. epidermidis and P. acnes was contributed by the major aroma components, terpinen-4-ol, α-terpineol and α-pinene [89]. However, terpene and limonene in tea tree oil caused allergies in hypersensitive skin [90]. Thus, caution regarding the dose used should be taken. However, adverse reaction of tea tree oil is rare. Therefore, it is one of the most popular and effective over-the-counter acne treatments [45]. In addition, juniper (Juniperus communis) oil was also found to be effective in the treatment of acne [87].

Licorice or Glycyrrhiza glabra, an herb native to Asian countries, was topically applied in the treatment of acne [91] because of its anti-inflammatory effect [92]. However, its anti-oxidant activity was low [93]. In addition, Gossypium barbadense, an anti-microbial and anti-oxidant herb [94], was used as a folk remedy for acne in Yemen owing to its biologically active terpenoids [95].

Basil or O. gratissimum was used to treat acne both in combination with A. vera gel [96] or alone [97] because of the powerful anti-inflammatory activity of the containing linolenic acid [98].

Rosa damascene, which is mostly used as a fragrance, was found to effectively inhibit P. acnes with respect to its anti-inflammatory action [99]. Similarly, rose oil was used in the treatment of acne [87]. Therefore, rose should be incorporated into cosmetic products as a multifunctional ingredient. Red clover or Trifolium pretense was employed as an acne remedy because of its anti-inflame flavonoids [100].

Subjectively used herbs

In addition to the aforementioned herbal extracts, the following herbs have been used subjectively in acne treatment:

The anti-inflammatory effects of Roman and German chamomiles (Anthemis nobilis and Matricaria recutita) were applied in skin inflammation treatment owing to their biologically active flavonoids, particularly apigenin, α-bisabolol and chamazulene [101].

Comparable activity against P. acnes and S. epidermidis was found between tea tree and Abies koreana oils containing bornyl acetate, limonene, α-pinene and camphene as the main compounds. In addition to acne pathogenesis inhibition, A. koreana oil exhibited anti-inflammatory effects towards LPS, TNF, IL, NO and PG [102]. In addition to those mentioned biologically active essential oils, S. epidermidis was found to be inhibited by Salvia sclarea (minimum inhibitory concentration; MIC = 1.5–2 mg ml−1) [103] and Ziziphora clinopodioides [104] oils. Furthermore, the essential oils of Anthemis aciphylla [105] and Tamarix bovena [105] were found to inhibit facial flora that would applicable in acne care product.

Eucommia ulmoids, a traditional tonic used in East Asia, was found to potently inhibit P. acnes (MIC = 0.5 mg m−1) and reduced the secretion of proinflammatory cytokines [99]. Thus, this herb should be further formulated in acne care products and clinically evaluated to prove its efficacy in human volunteer.

The susceptibility of P. acnes and S. epidermidis was tested on hop (Humulus lupus)-isolated compounds, lupulones and xanthohumol. Lupulones were the most potent bactericidal compounds against P. acne and S. epidermis at a MIC of 0.1 μg ml−1, whereas xanthohumol, a strong S. epidermidis inhibitor, showed stronger anti-oxidant activity [107].

Jojoba liquid wax, a common ingredient of cosmetics, was found to effectively reduce neutrophil infiltration by reducing myeloperoxidase activity. Nitric oxide level was reduced as well as TNF-α release [108], which is appraisal for inflammatory acne treatment.

The oriental anti-inflammatory herb [109], Magnolia officinalis, has long been used in East Asian countries. Its magnolol and honokiol potently inhibit P. acnes and P. granulosum (MIC = 3–4 and 9 μg ml−1, respectively) with the proven anti-inflammatory effects [110].

Radical scavenging activities of emblica or Phyllanthus emblica were found to be appropriate for acne treatment because of its active components that were mainly ascorbic acid, gallic acid and skin whitening agents, quercetins, and ellagic acid. In particular, the isolated geraniin showed the highest activities in DPPH and lipid peroxidation assays as well as NO scavenging activity [111–114].

Biological activity assessments of Punica granatum, which is an edible fruit, were made using radical, lipid peroxidation and superoxide assays [115]. Its anti-oxidant quality was high highlighting its capacity in the development of acne care products that have already been commercialized in Asia.

The inhibition of NO production and scavenging activity of Selginella involvens were found to be dose dependent. This herb also has an anti-inflammatory effect towards IL in keratinocytes. Furthermore, its non-antibiotic, anti-microbial potential on P. acnes has been reported and was non-cytotoxic at a concentration <50 μg ml−1 [116].

There were anti-inflammatory reports of Chinese medicinal plants root and leaf extracts. These include Aralia continentalis via inhibition of cyclooxygenase-2 (COX-2) and NO expression including NF-κB deactivation [117]. Clerodendron trichotomum was found to suppress PGE2 production [118], which appropriates for inflammatory acne treatment.

Prevention of acne was traditionally carried out using Ayurvedic formulations containing Curcuma longa [80, 119], which have anti-bacterial and anti-inflammatory activities [120]. This plant has long been used in Thai folk remedies for skin care and for its aromatherapy aspects in various traditional preparations, for instance masks, and compresses.

Garcinia mangostana is another economic fruit of Thailand. Its pericarp consisted of xanthones that potently inhibit P. acnes and S. epidermidis [121]. These anti-bacterial activities were found increased in a mature fruit [122]. Furthermore, it was found to be highly effective in free radical scavenging following P. acnes induction and suppressed the production of TNF-α, a pro-inflammatory cytokine [123], particularly in young fruit [122].

The anti-inflammatory effects of free fatty acid in sebum particularly linoleic and lauric acids were found to inhibit P. acnes [124]. Therefore, plants containing linoleic acid may be applicable in acne lesion reduction. Sunflower (Helianthus annuus) and pumpkin (Cucurbita pepo) seed oils as well as flax or linseed oil (Linum sp.), which have a high fatty acid content mainly linoleic and linolenic acids, were incorporated into a preparation for dermatological treatments including acne [125]. In addition to those natural oils, apricot (Prunus armeniaca), argan (Argania spinosa), avocado (Persea gratissima), baobab (Adansonia digitata), black currant seed (Rines nigrum), borage seed (Borago officinalis), cranberry seed (Vaccinium macrocarpon), corn (Zea mays), cotton seed (Gossypium sp.), evening primrose (Oenothera biennis), grape seed (Vitis vinifera), hazelnut (Corylus americana), manketti nut (Schinziophyton rautanenii), moringa (Moringa oliefera), palm (Elaesis guineensisi), poppy seed (Papaver orientale), rapeseed (Brassica napus), raspberry seed (Rubus idaeus), rice bran (Oryza sativa), safflower (Carthamus tinctorius), sesame (Sesamum indicum), soybean (Glycine soja), sweet almond (Prunus amygdalus), walnut (Juglans regia) and wheat germ (Triticum vulgare) oils, which contain more than 10% (w w−1) of linoleic acid [126], are used in the treatment of acne. However, evaluation of these vegetable oils in acne treatment should be performed.

Furthermore, salicylic acid that is used to remove follicular clog in acne treatment in addition to its skin peeling effect that significantly reduced comedones with less irritation than retinoids [45] has been found in several herbs. Salicylic acid was originally isolated from meadowsweet (Spiraea ulmaria) or Filipendula ulmaria [127, 128] including F. hexapetala [129] and willow (Salix alba) [130]. Anise, bay, basil, canella, caraway, cayenne, celery, cinnamon, chilli, coriander, fenugreek, parsley, mint, mustard, oregano, paprika, pepper, rosemary, sage, turmeric and thyme are used as natural sources of salicylic acid [131, 132]. These herbs and spices in addition to fruits, for instance lemon, have been found to contain free salicylic acid in high content [133].

As previously mentioned, azelaic acid is an efficacious acne treatment. Therefore, herbs containing azelaic acid should be effective in the treatment of acne. Sorghum bicolor is a cereal crop that contains azelaic acid and linoleic acid in adequate yield [134] similar to wheat, rye and barley that contain azelaic acid.

Thus, application of these mentioned herbs is appraisal in acne care product supplying highly interest and demand in naturally derived cosmetics.

Discussion

  1. Top of page
  2. SynopsisRésumé
  3. Introduction
  4. Sebaceous glands in acne formation
  5. Propionibacterium acnes in acne formation
  6. Reactive oxygen species in acne formation
  7. Active ingredients for topical acne treatment
  8. Herbs for acne treatment
  9. Discussion
  10. Conclusion
  11. Acknowledgement
  12. References

Tea tree oil has been widely commercialized as an over-the-counter acne treatment and may be preferred owing to its efficacy and safety. However, the oriental tonic particularly E. ulmoids is considered an alternative herb for acne treatment as its crude extract potently inhibits P. acnes as well as magnolia and hop. Those of linoleic acid–enriched and azelaic acid–enriched herbs are capable for anti-acne formulation development, especially sorghum. Similarly, the essential oils especially from S. sclarea and Z. clinopodioides should be developed into anti-acne products as well as from A. koreana in addition to their functions as fragrance. In particular, rose should be promoted as a multifunction active ingredient for acne treatment. Moreover, those edible fruits with anti-oxidant and anti-bacterial activities, for example G. mangostana, P. emblica and P. granatum, should be developed as acne care products.

Conclusion

  1. Top of page
  2. SynopsisRésumé
  3. Introduction
  4. Sebaceous glands in acne formation
  5. Propionibacterium acnes in acne formation
  6. Reactive oxygen species in acne formation
  7. Active ingredients for topical acne treatment
  8. Herbs for acne treatment
  9. Discussion
  10. Conclusion
  11. Acknowledgement
  12. References

The herbs summarized in Tables I and II were found to effectively reduce inflammatory acne lesions through mechanisms related to sebaceous glands, P. acnes and ROS. However, an appropriate delivery system should be developed to impart their efficacies in addition to the standardization of these herbs. Furthermore, an optimized and effective dose should be evaluated prior to the development of preparations in order to avoid irritation or allergy in subjects with hypersensitive skin. Strict quality control will ensure their safety and efficacy. In addition, combination treatment should be conducted as it was found to be more effective than the application of a single product with regard to synergistic effects on the pathogenesis of acne.

Table I.   Functions and applications of herbs for topical acne treatment
NameFunctionApplication/Dosage
Abies koreanaP. acnes and S. epidermidis inhibitions and anti-inflame [102]Essential oil
Allium cepaAnti-inflame [83]Poultice
Aloe veraAnti-inflame [80–82]Cream, gel
Anthemis aciphyllaAnti-bacterial [105]Essential oil
Anthemis nobilisAnti-inflame [101]Cream, ointment
Aralia continentalisAnti-inflame [117]Not available
Azadirachta indicaAnti-inflame [80]Cream, gel, essential oil
Centella asiaticaWounds and acne scar healings [86]Tonic
Clerodendron trichotomumAnti-inflame [118]Not available
Curcuma longaAnti-bacterial, anti-inflame [80, 82, 119]Cream, gel
Garcinia mangostanaP. acnes and S. epidermidis inhibitions, anti-oxidant [121–123]Not available
Glycyrrhiza glabraAnti-inflame, anti-oxidant [91–93]Not available
Gossypium barbadenseAnti-microbial, anti-oxidant [94, 95]Decoction
Eucommia ulmoidesP. acnes inhibition and anti-inflame [99]Tonic
Hemidesmus incidusAnti-inflame [80, 82]Cream, gel
Humulus lupusP. acnes and S. epidermidis inhibitionsand anti-oxidant [107]Not available
Magnolia officinalisP. acnes and P. granulosum inhibitionsand anti-inflame [110]Decoction
Matricaria recutitaAnti-inflame [101]Cream, ointment
Melaleuca alternifoliaP. acnes, S. aureus and S. epidermidis inhibitions[87–89]Cream, gel, essential oil
Ocimum gratissimumAnti-inflame [96, 97]Gel
Phyllanthus emblicaAnti-oxidant [111–114]Not available
Punica granatumAnti-oxidant [115]Not available
Rosa damasceneP. acnes inhibition and anti-inflame [99]Tea
Salvia sclareaS. epidermidis inhibitions [103]Essential oil
Selginella involvensAnti-inflame, anti-oxidant and P. acnes inhibition [116]Not available
Tamarix bovenaAnti-microbial [106]Essential oil
Trifolium pretenseAnti-inflame [100]Lotion
Ziziphora clinopodioidesS. epidermidis inhibition [104]Essential oil
Table II.   Herbs enrich active compounds against acne
Active compoundsHerbs
Terpinen-4-ol, α-terpineol, α-pineneAustralian eucalyptus and tea tree oils [89]
Apigenin, α-bisabolol, chamazuleneRoman and German chamomiles [101]
Magnolol, honokiolMagnolia [110]
Lupulones, xanthohumolHop [107]
Linoleic and lauric acidsApricot, argan, avocado, baobab, black currant seed, borage seed, cranberry seed, corn, coconut, cotton seed, evening primrose, grape seed, hazelnut, linseed, manketti nut, moringa, palm, poppy seed, pumpkin, rapeseed, raspberry seed, rice bran, safflower, sesame, sorghum, soybean, sunflower, sweet almond, walnut, wheat germ [124–126, 134]
Salicylic acidAnise, bay, basil, canella, caraway, cayenne, celery, cinnamon, chilli, coriander, fenugreek, parsley, meadowsweet, mint, mustard, oregano, paprika, pepper, rosemary, sage, turmeric, thyme, willow [127–132]
Azelaic acidBarley, rye, sorghum, wheat [134]

References

  1. Top of page
  2. SynopsisRésumé
  3. Introduction
  4. Sebaceous glands in acne formation
  5. Propionibacterium acnes in acne formation
  6. Reactive oxygen species in acne formation
  7. Active ingredients for topical acne treatment
  8. Herbs for acne treatment
  9. Discussion
  10. Conclusion
  11. Acknowledgement
  12. References