Comprehensive review of hepatotoxicity associated with traditional Indian Ayurvedic herbs

Abstract

With growing antipathy toward conventional prescription drugs due to the fear of adverse events, the general and patient populations have been increasingly using complementary and alternative medications (CAMs) for managing acute and chronic diseases. The general misconception is that natural herbal-based preparations are devoid of toxicity, and hence short- and long-term use remain justified among people as well as the CAM practitioners who prescribe these medicines. In this regard, Ayurvedic herbal medications have become one of the most utilized in the East, specifically the Indian sub-continent, with increasing use in the West. Recent well-performed observational studies have confirmed the hepatotoxic potential of Ayurvedic drugs. Toxicity stems from direct effects or from indirect effects through herbal metabolites, unknown herb-herb and herb-drug interactions, adulteration of Ayurvedic drugs with other prescription medicines, and contamination due to poor manufacturing practices. In this exhaustive review, we present details on their hepatotoxic potential, discuss the mechanisms, clinical presentation, liver histology and patient outcomes of certain commonly used Ayurvedic herbs which will serve as a knowledge bank for physicians caring for liver disease patients, to support early identification and treatment of those who present with CAM-induced liver injury.

Keywords: Ayurveda; Complementary and alternative medicines; Drug induced liver injury; Herb induced liver injury; Chronic liver disease; AYUSH system

Core Tip: Ayurvedic herbal medications (AHM) can cause liver injury ranging from an asymptomatic elevation of liver enzymes to cirrhosis and portal hypertension. Patients who develop AHM-related liver injury have a history of consumption of complex polyherbal formulations. In most cases, identification of the offending hepatotoxic agent is difficult due to the number and complexity of herbs involved. However, multiple observational studies, quality case series, and well-performed case studies have demonstrated the hepatotoxic potential associated with certain herbs used in Ayurvedic practice. The commonly utilized and over-the-counter available Indian herbs or their extracts, such as Ashwagandha, Aloe vera, Guggul, Puncture vine, Turmeric, Gotu-kola, Bakuchi, Senna, Noni, Malabar tamarind, and Gurmar have been associated with various types of liver injury ranging from acute self-limiting hepatitis, chronic hepatitis, prolonged cholestasis, hepatic sinusoidal obstruction syndrome, cirrhosis, and portal hypertension and can present clinically as acute severe liver injury, acute liver failure, acute decompensation of cirrhosis or acute on chronic liver failure. Physician knowledge regarding regional and local complementary and alternative practices among the general and patient population is essential in identifying those who develop complications of liver disease secondary to herbal hepatotoxicity, to make optimal treatment decisions, and for early prognostication.