Insights on the Anti-inflammatory Mechanism of the Polyphenolic-Rich Fraction of Glyphaea brevis (Spreng.) Monachino (Tiliaceae) Leaves

Glyphaea brevis (Spreng.) Monachino has been employed folklorically in West Africa for decades to manage inflammatory disorders such as peptic ulcer, edema, dyspepsia, and worm infestations; however, these pharmacological activities have not been scientifically proven. The study investigated the chemical composition and in-vitro/in-vivo anti-inflammatory capabilities of the polyphenolic-rich fraction of G. brevis leaves (PREG). In-vitro anti-inflammatory indices were evaluated using the human red blood cell (HRBC) methods. The acute lethality (LD50) test was demonstrated in mice with graded dosages (10 to 5000 mg/kg body weight of PREG) via oral intubation. While in-vivo anti-inflammatory activity was determined using a mice model inflicted with an intraperitoneal injection of 0.1ml of undiluted fresh egg albumin paw edema using egg albumin. All parameters were assayed according to standard protocols. High levels of tannins, phenols, flavonoids, and minimum amounts of terpenoids, steroids, alkaloids, and saponins were observed in PREG. The LD50 test demonstrated no toxicity and mortality in mice up to 5.0 g/kg bw p.o. PREG. The anti-inflammatory assays showed that at the different concentrations (0.2 - 1.0 mg/ml), PREG effectively inhibited albumin denaturation, platelet aggregation, hypotonicity-induced hemolysis, protease, and phospholipase A2 activity, as the standard drugs (Aspirin and Prednisolone). Also, PREG suppressed significantly (p< 0.05) the progression of egg albumin-induced mice paw edema, and these increased with time (0.5 - 5h). The maximum percentage of edema inhibition (91.4%) was observed in mice administered with 400 mg/kg bw PREG, and this was close to that (94.49%) obtained in the group administered with the reference drug (Indomethacin). These give insights into the anti-inflammatory potential of PREG.