Sustainable utilization of bottle gourd by-products: A nutritional and functional perspective

Bottle gourd (Lagenaria siceraria) is a highly nutritious vegetable with a long history of culinary and medicinal uses. In particular, it is an excellent source of dietary fiber (0.5–1.2 %), protein (0.6–1.2 %), carbohydrates (2.5–3.9 %), essential fatty acids, micronutrients like potassium (170–200 mg/100 g), calcium (20–25 mg/100 g), and vitamin C (10–12 mg/100 g). Besides, its by-products, i.e., seeds, peel, and leaves, are rich in bioactive compounds such as phenolic acids (25–98 mg GAE/g), flavonoids (15–75 mg QE/g), lignans, glycosides, saponins, cucurbitacins, and triterpenoids (5–40 mg/g), mainly responsible for its antioxidant, anti-inflammatory, antidiabetic, and antimicrobial activities. Despite holding great pharmacological promises, these by-products are often overlooked or not fully utilized, particularly in industrial food systems. There is still space for thorough investigations of their functionality, bioavailability, and potential integration into conventional food products. Indeed, there has been a little focus on fruit in most studies, a thorough biochemical characterization and clinical verification of the by-products are scarce. Considering these gaps, this review integrates current and available scientific data on the physicochemical composition, pharmacological activity, and ethnomedicinal relevance of bottle gourd and its wastes. Mainly, it emphasizes the need for immediate research aimed at valorizing its by-products, such as their incorporation into functional food products. Further, it investigates the use of bottle gourd in circular economy strategies for ensuring sustainability in agriculture and food sectors by minimizing losses and maximizing resource efficiency. Overall, this review breaks new grounds for interdisciplinarity research and innovation, calling for the exploitation of bottle gourd as a main ingredient in functional foods, nutraceuticals, and eco-friendly food systems. Finally, it seeks further exploration into new extraction methods, clinical establishment of therapeutic value, and commercialization-friendly formulations that will tap the complete nutritional and medicinal potential of this underappreciated crop.