Anti-nociceptive activity of Pereskia bleo Kunth. (Cactaceae) leaves extracts

Ethnopharmacological relevance: Local communities in Malaysia consume Pereskia bleo Kunth.

(Cactaceae) leaves as raw vegetables or as a concoction and drink as a tea to treat diabetes,

hypertension, rheumatism, cancer-related diseases, inflammation, gastric pain, ulcers, and for revitaliz-
ing the body.

Aim of the study: To evaluate anti-nociceptive activity of the extracts and vitexin, isolated for the first

time in this species, in two analgesic models; formalin-induced licking and acetic acid-induced

abdominal writhing.

Materials and methods: Three and a half kilos of P. bleo leaves were extracted using Soxhlet apparatus

with ethanol for 72 h. The crude ethanol extract was treated with activated charcoal overnight and

subjected to a liquid–liquid partition yielding hexane, dichloromethane, ethyl acetate and butanol

extracts. All extracts, including the crude ethanol and vitexin isolated from the ethyl acetate partition

were tested for peripheral anti-nociceptive activity using formalin test and acetic acid-induced

abdominal writhing, besides having their acute toxicity assays performed.

Results: The phytochemical analyses resulted in the isolation of vitexin (1), b-sitosterol glucoside

(2) and b-sitosterol (3) isolated from the ethyl acetate, dichloromethane and hexane extracts,

respectively. This is the first time vitexin and b-sitosterol glucoside are isolated from this species.

The anti-nociceptive activities for all extracts were only moderate. Vitexin, which was isolated from the

ethyl acetate extract did not show any activity in all models tested when used alone at the same

concentration as it appears in the extract.

Conclusion: This study showed that all the extracts possess moderate anti-nociceptive activity. Vitexin

is not the compound responsible for the anti-nociceptive effect in the ethyl acetate extract. Further

investigations are needed to identify the compound(s) that might be responsible for the anti-
nociceptive activity in this plant.