Secondary Metabolites from Ophiorrhiza

Ophiorrhiza is a genus of flowering plants with about 400 species. Phytochemical studies spanning last four decades resulted in the isolation of nearly 100 secondary metabolites, mostly alkaloids and anthraquinones, from various Ophiorrhiza species. This mini review summarizes the phytochemistry, camptothecin (CPT) screening, tissue culture-based CPT source enhancement and biological activities of the genus Ophiorrhiza. The major secondary metabolites isolated from genus Ophiorrhiza are alkaloids (49), anthraquinones (20), triterpenoids (8), diterpenes (1), sesquiterpenes (3), monoterpenes (1), steroids (6), flavonoids (2), coumarins (1), iridoids (6) and phenolic acids (2). Primary metabolites such as xanthophylls (1), pheophytins (2) and fatty acids (3) were also reported from some Ophiorrhiza species. CPT, owing to its anticancer applications, is the prominent biologically active entity found in various Ophiorrhiza species. Studies also reported the screening for elite Ophiorrhiza species/varieties with high CPT contents. Ophiorrhiza mungos and Ophiorrhiza mungos var. angustifolia showed highest CPT contents, whereas some Ophiorrhiza species/varieties showed zero or non-detectable levels of CPT. Ophiorrhiza species, mainly Ophiorrhiza pumila, were regenerated through tissue culture systems, and enhancement of their CPT contents was attempted by various groups. Most Ophiorrhiza species are still not subjected to phytochemical investigations, and these plants could provide more industrially important molecules and drug precursors.