Optimization of the extraction protocol to uptake the flavonoid content from jamaican cherry (Muntingia calabura L.) leaves extract as a source for an antifungal bioproduct development

Muntingia calabura is a plant species that is less susceptible to pests and fungi and has been widely cultivated as an undemanding plant in southern Vietnam, exhibiting a wide range of bioactive activities. These leaves are used as fertilizers and waste materials, profoundly emphasizing the source of bioproducts for crops serving sustainable agro-industry. This study investigates optimal extraction techniques to uptake the flavonoid content derived from Muntingia calabura leaves, focusing on the extraction condition and utilizing the response surface methodology linked with the Box-Behnken design, with the assistance of ultrasound waves. The results indicate that implementing ultrasonic treatments and optimal extraction conditions using 71% ethanol for 5.7 h at 45 °C significantly enhances the overall flavonoid content, reaching 221.57 mg GAE per extract. Effective parameters included a minimum inhibitory concentration of 10,000 μg/mL, these conditions yielded in inhibiting the fungi Botryosphaeria dothidea, Lasiodiplodia theobromae, and Lasiodiplodia pseudotheobromae, bringing the optimal flavonoid extract approach to meeting the antifungal properties. The bioactive product illustrated a notable capacity to inhibit the growth of three pathogenic fungi on jackfruit pedicle and jackfruit. This research indicated that the rich flavonoids antifungal bio-product from Muntingia calabura leaf extract offers a safe and effective alternative to synthetic chemical fungicides.