Punica Granatum Flower and Hibiscus Sabdariffa Calyx: A Narrative Review of Phytochemistry, Antioxidant Mechanisms, and Synergistic Potential in Oxidative Stress Management

Oxidative stress, resulting from an imbalance between free radical production and antioxidant defense mechanisms, underlies the pathogenesis of numerous chronic diseases including cardiovascular disorders, cancer, diabetes, and neurodegenerative conditions. The global burden of these diseases continues to rise, with cardiovascular diseases alone causing 19.2 million deaths annually. In Yemen, non-communicable diseases account for 42% of total deaths, with substantial underdiagnosis of conditions like type 2 diabetes highlighting urgent needs for accessible preventive interventions. This narrative review synthesizes the literature on two medicinal plants with significant antioxidant potential: Punica granatum (pomegranate) flower and Hibiscus sabdariffa (roselle) calyx. Both species are cultivated in Yemen and hold prominent positions in traditional medicine. Pomegranate flowers are rich in ellagitannins, particularly punicalagin, which constitute the predominant phytochemical class and are metabolized by gut microbiota to urolithins with enhanced bioavailability.[1-5] Hibiscus sabdariffa calyces contain high concentrations of anthocyanins, primarily delphinidin-3-O-sambubioside and cyanidin-3-O-sambubioside, along with organic acids including hibiscus acid and phenolic compounds such as chlorogenic acid.[6-10] Both extracts demonstrate potent antioxidant activities through multiple mechanisms including direct reactive oxygen species scavenging, metal chelation, activation of the Nrf2 signaling pathway, and upregulation of endogenous antioxidant enzymes.[11-15] Their complementary phytochemical profiles and mechanisms of action provide a strong scientific rationale for polyherbal combinations targeting oxidative stress-related disorders. This review consolidates evidence supporting the traditional uses, phytochemistry, and pharmacological properties of these two Yemeni medicinal plants.