Lotus corniculatus L. (Fabaceae) is widely grown in Egypt. It has a great history of folkloric medicinal uses. All fractions of aerial parts of L. corniculatus L. showed significant antioxidant and immunostimulant activities and could strongly induce lymphoproliferation. However, the light petrol fraction had antifungal activity against C. neoformans with IC50 value (<8 µg/mL) and exhibited strongest in-vitro antiprotozoal activity against protozoan parasites belonging to the genera Trypanosoma with IC50 value (0.98 µg/mL) and Plasmodium (with 100% inhibition using a sample concentration of 15866.7 ng/mL). This is the first study of the immunostimulant and antiprotozoal activities of genus Lotus. By this approach, it was possible to isolate eight compounds (-)-7,2'-dihydroxy-4'-methoxyisoflavan (vestitol) (1), kaempferol (2), kaempferol 3-O-α-L-rhamnoside (afzelin) (3), kaempferol 3, 7-O-α-L-dirhamnoside (kaempferitin) (4), kaempferol-3-O-[β-D-xylopyranosyl (1″'→2″)-β-D-galactopyranoside] (5), 3-O-[β-D-glucuronopyranosyl] soyasapogenol B (6), kaempferol-3-O-[β-D-xylopyranosyl (1″'→2″)-β-D-galactopyranoside]-7-O-α-L-rhamnopyranoside (7) and 3-O-[α-L-rhamnopyranosyl (1″'→2″)-β-D-galactopyranosyl-(1″→2')-β-D-glucuronopyranosyl] soyasapogenol B (soyasaponin І) (8).
Keywords: Lotus corniculatus L; antiprotozoal; immunostimulant; soyasaponin І.