Herbal medicines for liver diseases in India
Dr SP Thyagarajan, Department of Microbiology, Dr ALM Post Graduate Institute of Basic Medical Sciences, University of Madras, Taramani, Chennai 600 113, India. Email: firstname.lastname@example.org
Abstract The use of natural remedies for the treatment of liver diseases has a long history, starting with the Ayurvedhic treatment, and extending to the Chinese, European and other systems of traditional medicines. The 21st century has seen a paradigm shift towards therapeutic evaluation of herbal products in liver diseases by carefully synergizing the strengths of the traditional systems of medicine with that of the modern concept of evidence-based medicinal evaluation, standardization of herbal products and randomized placebo controlled clinical trials to support clinical efficacy. The present review provides the status report on the scientific approaches made to herbal preparations used in Indian systems of medicine for the treatment of liver diseases. In spite of the availability of more than 300 preparations for the treatment of jaundice and chronic liver diseases in Indian systems of medicine using more than 87 Indian medicinal plants, only four terrestrial plants have been scientifically elucidated while adhering to the internationally acceptable scientific protocols. In-depth studies have proved Sylibum marianum to be anti-oxidative, antilipidperoxidative, antifibrotic, anti-inflammatory, immunomodulating and liver regenerative. Glycyrrhiza glabra has been shown to be hepatoprotective and capable of inducing an indigenous interferon. Picrorhiza kurroa is proved to be anti-inflammatory, hepatoprotective and immunomodulatory. Extensive studies on Phyllanthus amarus have confirmed this plant preparation as being anti-viral against hepatitis B and C viruses, hepatoprotective and immunomodulating, as well as possessing anti-inflammatory properties. For the first time in the Indian systems of medicine, a chemo-biological fingerprinting methodology for standardization of P. amarus preparation has been patented.
© 2002 Blackwell Publishing Asia Pty Ltd
The use of herbal medicine can be traced back to 2100 bc in ancient China at the time of Xia dynasty, and in India during the Vedic period. The first written reports are timed to 600 bc with Charaka samhita of India, and in China the same became systematic by 400 bc.1 The basic concept in these medicinal systems is that the disease is a manifestation of a general imbalance of the dichotomous energies that govern life as a whole and human life in particular, and they focus on medicine that can balance these energies and maintain good health. In Ayurvedha of India, the forces are said to be agni (strength, health and innovation) and ama (weakness, disease and intoxication). In India there are also other systems of traditional medicine besides Ayurvedha and these are called Siddha, which originated almost at the same time as Ayurvedha from southern India, and Unani, which entered India during the Mogul dynasty periods. Like Ayurvedha, practitioners of Siddha medicine believe in a perfect balance of three doshas known as vatha (space and air elements), pitta (fire and water elements) and kapha (water and earth elements). All these Indian systems of medicine have primarily claimed a curative potential for their medicinal preparations for all kinds of liver diseases.
In spite of the significant popularity of these medicinal systems, they are still to be recognized as being universally acceptable treatment modalities for chronic liver disease.
The limiting factors that contribute to such an eventuality are (i) lack of standardization of the herbal drugs; (ii) lack of randomized placebo controlled clinical trials; and (iii) lack of traditional toxicologic evaluations.
Herbal preparations used in indian systems of medicine
There are more than 300 preparations in the Indian systems of medicine for the treatment of jaundice and chronic liver diseases (Tables 1–3).
Table 1. Siddha medicine preparations approved by the Indian Medicinal Practitioner's Co-operative Pharmacy and Stores for the treatment of jaundice and chronic liver diseases 2
|2.||Annabedhi chendooram no. 1 and 2.|
|7.||Kantha chendooram and|
Table 2. Ayurvedic preparations approved by the Indian Medicinal Practitioner's Co-operative Pharmacy and Stores for the treatment of jaundice and chronic liver diseases 2
| 3.||Drakahadi rasayam.|
| 4.||Guduchi satwam.|
| 5.||Jambeeradi panakam.|
| 6.||Panchatiktakwatha churnam.|
| 7.||Dhathri loham.|
| 8.||Tapyadi loham.|
| 9.||Pipilyadi loham.|
Table 3. Unani preparations approved by the Indian Medicinal Practitioner's Co-operative Pharmacy and Stores for the treatment of jaundice and chronic liver diseases 2
| 2.||Jawarish-e-Amila luluvi.|
In India more than 87 medicinal plants are used in different combinations as herbal drugs for liver diseases.3–6 However, not all the plants have been evaluated for their pharmacological and antiviral efficacy although several plants were reported as being hepatoprotective (Table 4).7–36
Table 4. List of the Indian medicinal plants having liver protection properties against chemical-induced liver damage in experimental animals 7–36
| 1.||Acacia catechu.|
| 2.||Achillea millfolium.|
| 3.||Azadirachta indica.|
| 4.||Andrographis paniculata.|
| 5.||Boerhaavia diffusa.|
| 6.||Capparis spinosa.|
| 7.||Chelidonium majus.|
| 8.||Cichorium intybus.|
| 9.||Daucus carota.|
Scientific validation in medicinal plant research in india
There are data available on the following plants: (i) Picrorhiza kurroa; (ii) Phyllanthus amarus (niruri); (iii) Silybum marianum; and (iv) Glycyrrhiza glabra.
Picroside 1 and 2, catapol, kutkoside I and kutkoside have been identified as major bioactive components of P. kurroa.37,38Picrorhiza kurroa, a known hepatoprotective plant, was studied in experimental and clinical situations. Basic research has been carried out on the whole plant, picroside 1 alone, and on picroliv, which contain picroside 1, catapol, kutkoside I and kutkoside.
Dwivedi et al. have shown significant hepato-protective properties of picroliv using models such as monocrotaline- and CCl4-induced liver injury in rats.38–40 Shukla et al. compared picroliv with silymarin in rat and guinea pig models and found potent choleretic and anticholestatic functions.41 Chander et al. also found hepatoprotective properties in picroliv.42 Using in vitro HBsAg binding assay, Mehrotra et al. have shown HBsAg inhibition in picroliv and its major component, catapol.37 Pandey and Das, and Atal Mehrotra et al. have demonstrated anti-inflammatory and immuno-modulating potential in P. kurroa, stimulating both cell-mediated and humoral immunity.43–45
Picrorhiza kurroa has also been found to be helpful in clinical and biochemical recovery in acute hepatitis. 46
Jayaram found P. kurroa to be effective in HBeAg seroconversion in 28.5% of patients compared to 16% seroconversion with placebo.47
The existing literature on P. kurroa suggests that it is a powerful immuno-modulator rather than an antiviral drug in liver diseases.
Historical use of Phyllanthus niruri in jaundice
Even though clinical uses of P. niruri and other species, namely P. amarus, have been cited for over a century in the Ayurvedha and Siddha literature, scientific studies were carried out only during the last 50 years.
Studies on Phyllanthus niruri/amarus against hepatitis B virus
Thyagarajan et al. have shown that there exist antiviral properties against HBV for the whole plant extract of P. niruri.48,49 This plant from Tamilnadu, India, has been identified taxonomically as P. amarus. The aqueous extracts of the plant inhibits the viral DNA polymerase (DNAp) of HBV and woodchuck hepatitis virus (WHV) in vitro.50–52
Yanagi et al. have also reported that aqueous extracts of high dilutions of P. amarus collected from South India inhibited HBV DNAp, DNApI, T4-DNAp, the Klenow fragment and reverse transcriptase of avian myeloblastosis virus.52 Shead et al. have shown the aqueous extracts to inhibit the endogenous DNAp of Duck hepatitis virus (DHBV) at high dilutions.53 Niu et al. with suitable controls found that after 10 weeks treatment, there was a transient reduction of duck hepatitis B viral DNA in the serum of congenitally infected ducks, but there was no effect on the level of virus DNA or surface antigen in the liver.54
Jayaram and Thyagarajan reported in vitro inhibition of HBsAg secretion by PLC/PRF/5 (Alexander) cell line for 48 h when the cell line was treated with 1 mg/mL concentration of P. amarus as a single dose.55 Lee et al. found that P. amarus downregulated HBVm transcription and replication in transgenic mice and transgenic cell lines.56Phyllanthus amarus possibly interrupts the interaction between HBV enhancer I and cellular transcription factors.57
Phyllanthus amarus is reported to be safe and non-toxic to mice in a dose of 10 g/kg bodyweight. 58 A 20% aqueous extract of P. niruri is effective as an oral pretreatment at 0.2 mL/100 mg bodyweight against CCl 4 -induced hepatotoxicity in rats. 59 The hexane-extracted compounds, phyllanthin and hypophyllanthin, were found to reduce CCl 4 - or galactosamine-induced cytotoxicity to cultured rat hepatocytes. 60
The aqueous extract of the dried whole plant did not produce any chronic toxicity in mice at 0.2 mg daily dose per animal for 90 days, as determined by physiological, biochemical and histopathological parameters.61 Venkateswaran et al. demonstrated its in vivo safety using woodchucks as animal models,50 while Niu et al. have shown P. amarus to be non-toxic in Pekin ducks chronically infected with duck hepatitis B virus.54 Jayaram et al., studying the effect of P. amarus on β-galactosamine-induced hepatotoxicity on isolated rat hepatocytes, found that P. amarus by itself was not hepatotoxic and at 1 mg/mL concentration it was found to be hepatoprotective.62
In the traditional medicine systems, several formulatory medicines are used for the treatment of jaundice without taking into consideration the etiology. Phyllanthus niruri is one of the constituents of such multiherbal preparations, which contain anywhere up to 12 medicinal herbs. Most of the treatment evaluations were based only on improvement in the clinical condition of the patient.
In a clinical trial in acute viral hepatitis (AVH) patients, Jayanthi et al. used P. niruri and compared it with other herbal medicines.63 A significantly greater decrease in transaminase levels after 2 weeks’ treatment with P. niruri in both HBsAg-positive and -negative groups was observed. In another study, P. amarus treatment improved liver functions significantly faster in both acute hepatitis A and B, with a higher rate of HBsAg clearance.64
In a clinical trial on chronic HBV carriers, HBsAg clearance in the P. amarus-treated group was 59%, versus 4% in the placebo group.65 The second open trial in 1990 showed 20% HBsAg clearance and 63.6% loss of infectivity by HBeAg sero-conversion.66 Additional clinical trials were undertaken in subsequent years (Table 5).69 However, several investigators from other countries including Leelarasamee et al. from Thailand and Wang et al. from China could not reproduce the treatment efficacy.67,68 This could partly be due to the use of the local variety of P. amarus grown in their respective countries.
Table 5. Clinical trials of Phylllanthus amarus on patients with chronic HBV
|1||Thyagarajan et al. (1988)65, Madras||200||1 month||40||38||59||4||ND||ND|
|2||Thyagarajan et al. (1990)66, Madras||250||3 months||20||Nil||20||–||63.6||–|
|3||Samuel et al. (1991)69, Vellore||250||2 months||10||12||20||8.3||37.5|| 0|
|4||Thyagarajan etal (1992)69, Madras||250||6 months||72||Nil||25||–||54.0||–|
|5||Thyagarajan etal (1993)69, Madras||500||3 months|| 8|| 8||25||0||71.4||16.0|
|6||Walker et al. (1993–1995)69, Glasgow||500||4–6 months||26||Nil||11.6||–||45.4||–|
|7||Thyagarajan et al. (1996–1997)69, |
Standardization of phyllanthus amarus
In order to determine the reasons for variation in the in vitro efficacy of different collections of P. amarus made from different parts of India, in vitro analysis for biological properties was done. It revealed that the quantitative HBsAg binding ability and HBV DNA polymerase inhibition ability varied significantly in different plant collections, and some of them did not possess demonstrable anti-hepatitis B properties. When the extracts of these collections were analyzed by HPLC profiles, there were similar variations of diminished elution peaks or even absence of such peaks that could be correlated with the absence of biological properties. These observations were considered along with the report of Mitra and Jain on the botanical survey of India, which stated that the P. niruri is a mixture of three distinct species, namely P. amarus Schum and Thonn, P. fraternus Webster and P. debilis Kleinx Wild.70 From the reports it is now understood that the variety that is predominant in South India is P. amarus only.71
Based on these observations it was necessary to define a multistep standardization procedure for assuring the reproducible, maximized bio-efficacy of P. amarus when used in the treatment of chronic liver disease with special reference to chronic HBV infection. These steps are: (i) taxonomic identification of the specific variety of P. amarus as the source material; (ii) preparation of the soil for the optimum growth of the selected P. amarus variety; (iii) a formulation of the combination of specific extracts that will possess the following six demonstrable in vitro activities: (a) HBsAg binding property, which will facilitate the inactivation of the virus in circulation, ultimately leading to viral clearance; (b) HBV-DNA polymerase enzyme-inhibiting potential, thus acting as an antiviral and preventing the multiplication of HBV; (c) reverse transcriptase enzyme inhibition, also required for the prevention of initiation of HBV replication; (d) inhibition of HBsAg secretion from HBV-transinfected liver cells, thus possessing activity against virus-infected chronic liver disease conditions; (e) hepatoprotective and antihepatotoxic properties against the liver cell toxicity brought about by all hepatitis viruses (A,B,C,D,E) and other hepatotoxic agents; and (f) immunomodulating property to potentiate the immune system of HBV-infected patients towards virus clearance and protective antibody (anti-HBs) responses; and (iv) a ‘chemobiological finger printing methodology’ using the aforementioned six biological tests along with a matching HPLC profile to assess batch-to-batch in vitro reproducibility.
The evaluation of herbal products face several major problems. The first is the use of mixed extracts (concoctions) and variations in methods of harvesting, preparing and extracting the herb, which can result in dramatically different levels of certain alkaloids. The biologically active substances have been structurally defined and standardized for only a few of the herbs. Even then it may not be known whether this is the sole active principal or if efficacy depends on the mixture of compounds.
Second, there is a lack of randomized placebo controlled clinical trials for many of these preparations using end-points of treatment efficacy such as viral clearance, and histological improvement.
Numerous reports on toxic effects contradict the popular view that herbal drugs are natural and are harmless.72–76 A survey by the National Poison Information Service for the years 1991–1995 documented 785 cases of possible or confirmed adverse reactions to herbal drugs, among which hepatotoxicity was the most frequent.73 Hence, safety studies are needed to generate scientifically sufficient data that may serve as a basis for future herbal drug development.
In addition to the well-accepted laboratory parameters as described here using P. amarus as an example, if the aforementioned three aspects viz., herbal drug standardization, randomized controlled clinical trials and well-designed safety studies are incorporated as integral components, then herbal drug development, potent, safe and acceptable herbal drugs can be launched for the treatment of acute and chronic liver diseases. The drug development of P. amarus in India may be an example of such an effort in an international setting.
The authors wish to acknowledge the collaboration extended by Late Dr N. Madanagopalan, Professor and Head, Department of Gastroenterology, Madras Medical College and other gastroenterologists of Tamilnadu; Dr Eric Walker, Scottish Center for Infection and Environmental Health, UK; Dr Stephen Locarnini, MacFarlane Center for Virology, Australia; and Dr Sanjeev Gupta, Albert Einstein Center for Liver Diseases, USA. The financial help extended by Indian Council of Medical Research, Council of Industrial and Scientific Research, India and the HEL Programme of British Council Division for the research by the authors on P. amarus is sincerely acknowledged.