Christian A Alalor¹ , Sinodukoo E Okafo¹, Kenneth O Akproko¹, Goodnews I Agare², Benedict B Iwetan²

Abstract

Purpose: To assess the wound recovery and anti-inflammatory activities of herbal nanogels formulated using Annona muricata extract (AME) in Wistar rats. Methods: The crude methanol extract from Annona muricata leaves was processed into a total of seven batches of topical gels (F1 - F7), three batches of nanogels (F1- 1 % AME nanogel, F2 – 2 % AME nanogel, F3 - 3 % AME nanogel), three batches of crude gels (F4 – 1 % AME crude, F5- 2 % AME crude, F6 – 3 % AME crude) and one batch of blank gel (F7). The anti-inflammatory effect was tested using paw edema generated by carrageenan, while the wound restoration effect was assessed on excision-induced rat wounds. Physicochemical evaluation of the gels included pH, viscosity, and spreadability. Results: The herbal nanogels at 3 %w/w demonstrated significant anti-inflammatory and wound healing effects (p < 0.05), surpassing corresponding concentrations of crude Annona muricata extract and comparing favorably with the standards. The nanogel formulations exhibited favorable physicochemical characteristics. The optimized formulation, F3 (3 % AME-Nanogel), displayed remarkable anti-inflammatory activity (p < 0.05), achieving 100 % edema inhibition after 5 hours and 94.87 % wound closure and epithelialization within 15 days, surpassing the corresponding concentration of crude AME at 92.59 and 90 %, respectively. Enhanced activity of the nanogel could be due to increased solubility and bioavailability of the extract by reducing particle size with a polydispersity index (PDI) of 0.404 and mean size of 73.35 nm. Conclusion: Extract of Annona muricata leaves possesses notable wound recovery and anti-inflammatory activities; the nanogel of Annona muricata extract enhanced the wound recovery and anti-inflammatory activities significantly, indicating its potential topical therapy for inflammation and wounds.