Streblus asper showed promising anti-allergic activity in experimental models. Anti-PCA (passive cutaneous anaphylaxis) and mast cell stabilizing activity of S. asper were investigated in mice and rats. Disodium cromoglycate (DSCG) was used as standard anti-allergic drug. Streblus asper (50–100 mg kg−1, p.o.) in mice showed 60–74% anti-PCA activity. In rats it showed dose-dependent (50–200 mg kg−1, p.o.) anti-PCA activity (56–85%). The mast cell stabilizing activity in rats (10 mg kg−1, p.o. × 4 days) showed 62% protection against comp. 48/80 induced degranulation. In egg albumin induced degranulation in sensitized rats there was 67% protection with S. asper. These results were comparable with that of DSCG (50 mg kg−1, i.p.) (45).
Insecticidal effects have been shown in extracts of the S. asper stem (46). Extracts from the stem bark of S. asper possess insecticidal activity against the fifth instar of Dysdercus cingulatus. Methanolic extract showed an LC50 value of 5.56 µg per insect. Partition with chloroform increased the insecticidal activity (LC50 2.01 µg per insect). Three polyphenolic rich fractions were obtained from silica gel column chromatography of the chloroform fraction and found to have noteworthy insecticidal activity (LC50: 1.82, 2.70 and 2.26 µg per insect) by topical application. This may provide a useful beginning for the development of biopesticides (47).
In vitro antitrypanosomal activity of aqueous extract of leaves of S. asper was studied at 5, 50, 500 and 1000 mg ml−1 (48). However, it did not show any significant activity and was thus not taken up for in vivo studies.
Das and Beuria (49) have studied the antimalarial property of the extract of S. asper in murine malaria. Giving the stem bark extract of S. asper intraperitoneally has been shown to stimulate a host immune response against Plasmodium berghei in mice.