Abstract

Plants of genus Ononis belong to family Fabaceae and are distributed in Europe, Atlantic Islands, West Asia, and North Africa and more than 75 species in the genus have been identified worldwide. Previous phytochemical studies showed a diversity of bioactive constituents, specifically flavonoids and isoflavonoids, that have been responsible for the different actions exerted by plants of this genus. This study represents a comprehensive review of all data present in literature related to the phenolic constituents isolated from Ononis plants and their pharmacological activities. The study revealed also the essential structure-activity relationship of Ononis compounds and briefly highlighted some toxicity studies. Data was collected by searching journals, books, periodicals, and databases. The results demonstrated a wide variety of flavonoids and isoflavonoids, isocoumarins, and resorcinols reported from different Ononis species. Flavonoidal compounds were the main constituents responsible for the various pharmacological activities such as antioxidant, anti-inflammatory, antimicrobial, cytotoxic, enzyme inhibitory, and antidiabetic effects. The reason behind these activities was mainly the degree and position of hydroxylation and methoxylation on the flavonoids’ rings. The findings of this study suggest Ononis plants and/or their components are promising candidates for treatment of wide range of ailments as a preventive measure or in combination with conventional therapies. Further studies would be required to describe the detailed mechanistic pathways for promising compounds and their clinical applications.

Key words: Ononis, Phytochemical constituents, Flavonoids, Pharmacological activities, Structure-activity relationship