Botany, ethnomedicines, phytochemistry and pharmacology of Himalayan paeony (Paeonia emodi Royle.)

Abstract Ethnopharmacological relevance Himalayan paeony ( Paeonia emodi Royle.) is an important species used to treat various diseases. This study aimed to compile the detailed traditional medicinal uses, phytochemistry, pharmacology and toxicological investigations on P. emodi . This study also highlights taxonomic validity, quality of experimental designs and shortcomings in previously reported information on Himalayan paeony. Methods The data was extracted from unpublished theses (Pakistan, China, India and Nepal), and different published research articles confined to pharmacology, phytochemistry and antimicrobial activities using different databases through specific keywords. The relevant information regarding medicinal uses, taxonomic/common names, part used, collection and identification source, authentication, voucher specimen number, plant extracts and their characterization, isolation and identification of phytochemicals, methods of study in silico, in vivo or in vitro, model organism used, dose and duration, minimal active concentration, zone of inhibition (antimicrobial study), bioactive compound(s), mechanism of action on single or multiple targets, and toxicological information. Results P. emodi is reported for diverse medicinal uses with pharmacological properties like antioxidant, nephroprotective, lipoxygenase inhibitory, cognition and oxidative stress release, cytotoxic, anti-inflammatory, antiepileptic, anticonvulsant, haemaglutination, alpha-chymotrypsin inhibitory, hepatoprotective, hepatic chromes and pharmacokinetics of carbamazepine expression, β-glucuronidase inhibitory, spasmolytic and spasmogenic, and airway relaxant. Data confined to its taxonomic validity, shows 10% studies with correct taxonomic name while 90% studies with incorrect taxonomic, pharmacopeial and common names. The literature reviewed, shows lack of collection source (11 reports), without proper source of identification (15 reports), 33 studies without voucher specimen number, 26 reports lack information on authentic herbarium submission and most of the studies (90%) without validation of taxonomic names using recognized databases. In reported methods, 67% studies without characterization of extracts, 25% lack proper dose, 40% without duration and 31% reports lack information on proper controls. Similarly, only 18% studies reports active compound(s) responsible for pharmacological activities, 14% studies show minimal active concentration, only 2.5% studies report mechanism of action on target while none of the reports mentioned in silico approach. Conclusion P. emodi is endemic to Himalayan region (Pakistan, China, India and Nepal) with diverse traditional therapeutic uses. Majority of reviewed studies showed confusion in its taxonomic validity, incomplete methodologies and ambiguous findings. Keeping in view the immense uses of P. emodi in various traditional medicinal systems, holistic pharmacological approaches in combination with reverse pharmacology, system biology, and “omics” technologies are recommended to improve the quality of research which leads to natural drug discovery development at global perspectives.