4.1 The CA fruit is rich in vitamins, minerals, dietary fiber, and antioxidants that help enhance immune function and promote cardiovascular health. In India, it has been extensively used in folk medicine to treat skin diseases, ulcers, indigestion, arthritis, and tumors, as well as to alleviate pain, repel insects, and combat malaria for a long time [4]. The unripe fruit contains tannins, which are used as astringents in medicines for the treatment of acute diarrhea and dysentery. The crushed leaves were frequently made into a paste for application on boils, blisters, and ulcers. As proven by modern pharmacological experiments, many medicinal properties of the fruit, like anticancer, anti-inflammatory, and regulation of blood sugar response, are primarily attributed to its bioactive compounds, such as flavonoids, terpenes, acetogenins, squamons, and alkaloids [21,44]. In conclusion, CA and its by-product are promising candidates for the development of novel functional foods and drugs, and the health benefits are displayed in Figure 2.
Figure 2. Below
4.3. Regulation of Blood Sugar Response
Diabetes mellitus involves chronic hyperglycemia, with herbal foods providing safe therapeutic alternatives. As a traditional Mexican ethnomedicine, CA (pulp, leaves, and peel) has been utilized for adjuvant management of hyperglycemia and diabetes, particularly during early disease stages [52]. It was confirmed that both CAP and CAL extracts exhibit significantly stronger inhibition of α-glucosidase and α-amylase activities compared to the standard drug acarbose [53]. In animal models, peel lyophilizate (100–200 mg/kg) effectively reduced postprandial glucose in healthy Wistar rats and significantly improved non-fasting capillary glucose, glucose intolerance, and insulin response in type two diabetic mellitus rats after a 14-day treatment [54]. Concurrently, leaf hydroalcoholic extract (three hundred fifty milligrams per kilogram) markedly lowered post-load blood glucose levels in both normoglycemic- and alloxan-induced diabetic rats, demonstrating antidiabetic effects comparable or superior to glyburide [55]. These findings collectively substantiate blood-glucose-regulating mechanisms and support its potential as an adjunctive therapy for type two diabetes mellitus.
4.4. Improvement of Cognitive Function
CAL shows potential activities for enhancing memory and preventing neurodegenerative disorders. In scopolamine-induced amnesia mouse models, CAL extract modulated the cholinergic system by reducing total acetylcholine and elevating choline acetyltransferase activity, effectively preventing memory impairment linked to oxidative stress and cholinergic dysfunction [56]. In amyloid-β-injected Alzheimer’s disease (AD) models, its ethanol extract significantly suppressed oxidative stress, neuronal death, amyloid-beta aggregation, and memory deficits via the epidermal growth factor receptor and G protein-coupled receptor kinase 2 pathways [57]. Collectively, CAL demonstrates promise as a therapeutic candidate for AD and functional food for cognitive improvement.
4.5. Prevention of Cardiovascular and Cerebrovascula Diseases
CA promotes cardiovascular health through multiple mechanisms, and its balanced potassium-to-sodium ratio helps stabilize blood pressure; abundant magnesium enhances myocardial function and relieves cramps, reducing risks of myocardial infarction and stroke. Niacin and dietary fiber regulate cholesterol levels while inhibiting intestinal absorption. Additionally, CA prevents free radical attacks on lipids, supporting heart health [21].
Health benefits of the custard apple and its extracts.
