Inhibition of the toxic effects of Bothrops asper venom by pinostrobin, a flavanone isolated from Renealmia alpinia (Rottb.) MAAS

Ethnopharmacological relevance: Renealmia alpinia has been traditionally used to treat snakebites by indigenous Embera-Katíos tribes belonging to the regions of Antioquia and Chocó, Colombia, and it has been shown to inhibit the enzymatic and biological activities of Bothrops venoms and their purified phospholipase A2 (PLA2) toxins. In addition to its common local usage against snakebites, Renealmia alpinia is commonly used to treat pain. To evaluate the inhibitory ability of pinostrobin, the main compound in the dichloromethane extract of Renealmia alpinia, on the toxic effects of Bothrops asper venom through in vitro and in vivo models and to evaluate its activity against pain and edema.

Materials and methods: Pinostrobin was isolated from the dichloromethane extract of Renealmia alpinia leaves. The protective properties of the extract and of pinostrobin against the indirect hemolytic, coagulant and proteolytic effects of Bothrops asper venom were evaluated in vitro, and the anti-hemorrhagic and anti-inflammatory activity were evaluated in vivo.

Results: Renealmia alpinia extract significantly inhibited the proteolytic activity and indirect hemolytic activity of Bothrops asper venom at a venom:extract ratio of 1:20. Moreover, the present data demonstrate that pinostrobin may mitigate some venom-induced local tissue damage due to hemorrhagic effects, and the compound is also responsible for the analgesic and anti-inflammatory activity of the extract from Renealmia alpinia. This is the first report to describe pinostrobin in the species Renealmia alpinia and its properties in vitro against Bothrops asper venom.

Conclusion: Our studies of the activity of Renealmia alpinia against the venom of Bothrops asper have confirmed that this species possesses inhibitory effects against Bothrops asper venom in both in vitro and in vivo models and that these effects may be due to pinostrobin, supporting the traditional usage of the plant. Additionally, pinostrobin may be responsible for the anti-hemorrhagic and analgesic activity (peripheral analgesic activity) of Renealmia alpinia.