Antioxidant, antibacterial and antiplasmodial activities of galactogogue plant extracts

Abstract

Galactogogue plants have been used traditionally worldwide to stimulate lactation. Research on antioxidant, antibacterial and antimalarial activities of the galactogogue plants are limited to a few of its species. Thus, this work aims to evaluate in vitro antioxidant (2,2-diphenyl-1-picrydydrazyl (DPPH) radical and 2,2´-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radical cation scavenging abilities, ferric reducing antioxidant power (FRAP), total phenolic content (TPC) and total flavonoid content (TFC)), and also antibacterial and antimalarial activities of sixteen galactogogue plants collected from northeastern Thailand. The antioxidant, antibacterial and antimalarial assays followed established procedures. Results indicated that the methanol and ethyl acetate extracts from the stem bark of Caesalpinia sappan (CS) and Ochna integerrima (OI) showed potent antioxidant capacity with the DPPH, ABTS and FRAP assays. These two particular plant extracts also possessed high TPC and moderate TFC. Both extracts of CS also exhibited good antibacterial activity, followed by extracts from OI which showed selective antibacterial activity toward three Gram-positive bacteria. The ethyl acetate extract from the stem bark of Siphonodon celastrineus (SCe), and the methanol and ethyl acetate extracts of Micromelum minutum (MM) also displayed strong antiplasmodial activity against Plasmodium falciparum. Our findings suggest that both CS and OI could be used as potential natural antioxidant and antibacterial (especially against Gram-positive bacteria) sources while MM and SCe could be promising alternative antimalarial plant for treating the P. falciparum parasites.