Herbal Medicines for Acute Kidney Injury: Evidence, Gaps and Frontiers

Acute kidney injury(AKI) is a major health threat worldwide. The literature on herbal intervention in AKI was searched from English and Chinese databases and reports were critically analyzed in terms of preventing AKI, promoting repair and regeneration, enhancing extrarenal clearance of uremic toxins, and preventing progression to chronic kidney disease(CKD). Altogether, 16 herbal formulae and a few extracts derived from individual herbs were reported to prevent or mitigate AKI in animal models induced by renal ischemia/reperfusion, cisplastin,gentamicin, glycerol, adenine, sepsis or physical exhaustion. Four formulae and six individual herbs were reported to accelerate recovery and/or to prevent CKD in established AKI animal models. Intrarectal herbal medicines, with or without simultaneous oral administration, were reported in six clinical trials and in an animal model to increase extrarenal clearance of uremic toxins. Additional 13 clinical trials reported oral or intravenous herbal interventions in AKI of different etiologies. Despite recurring problems, notably poor compliance with good practice guidelines for clinical trials and for authentication, naming and quality control of herbal materials, accumulating experimental data on the preventive effects of herbal medicines in AKI look encouraging and urge for better, definitive trials to guide clinical practice. Herbal enemas promoting extrarenal clearance of uremic toxins seem cost-effective, but better clinical evidence is certainly needed before any affirmative recommendation be made for AKI patients without access to dialysis. New frontiers, however, lie in those herbal remedies that promote repair/regeneration and prevent chronicity after AKI. Recent experimental data suggest that this may be possible.

THE REGISTRATION OF TCM PRODUCTS UNDER EU TRADITIONAL HERBAL MEDICINAL PRODUCT DIRECTIVE

The Traditional Herbal Medicinal Products Directive(THMPD)2004/24/EC is a regulatory process established to enable high quality herbal medicines to be registered as an OTC product,with medical claims(as allowed for OTC drugs)on the packaging and in the patient information leaflet.For those products which are eligible to be registered they must firstly,be only for mild and self-limiting ailments。

Gut Microbiota Brings a Novel Way to Illuminate Mechanisms of Natural Products in vivo

Poor bioavailability and undefined major/direct targets are two major obstacles for herbal medicines and natural products（NPs） to elucidate their precise mechanisms in vivo. Gut microbiota is an important bridge between eukayotic body and environment, which can interact with a majority of medicines with poor bioavailability and mediate their in vivo pharmacological activities. There are two main modes through which gut microbiota may mediate the pharmacological effects of NPs. First, gut microbiota catabolizes the NPs in herbal medicines into secondary metabolites with higher bioavialability and/or higher activity, facilitating the NPs enter circulation and exert beneficial impact at the pathological spot. Second, herbal medicines and NPs can favorably shift the compositional structure of gut microbiota, thereby performing remote functions to diseased organs/tissues via the systemic impaction of gut microbiota. In this review, the potential pathways were summarized through which gut microbes facilitate the pharmacological functions of herbal medicines and NPs and highlight the significance of gut microbiota in clarifying the in vivo mechanisms of herbal medicines and NPs.