Physicochemical, Structural and Elemental Analysis of Citrus limon and Citrus medica Leaves: Insights into Their Bioactive and Nutraceutical Potential

Abstract

The increasing global demand for sustainable, plant-based bioresources has intensified research on underutilized plant parts with nutritional and therapeutic potential. This study investigates the physicochemical, structural, and elemental characteristics of Citrus limon (lemon) and Citrus medica (citron) leaves to assess their suitability for nutraceutical and edible product applications. Fresh leaves were collected from Tirunelveli District, Tamil Nadu, authenticated by taxonomists, shade-dried, and powdered for analysis. Physicochemical evaluations including acidity, ash, moisture, and organoleptic parameters confirmed high quality, purity, and stability of both samples. C. medica exhibited greater acidity (7.8%) and mineral balance than C. limon (4.5%), reflecting richer organic acid content and bioactive potential. X-ray diffraction (XRD) analysis revealed semi-crystalline structures with dominant peaks at approximately 24° (2θ), indicating organized molecular arrangements associated with polyphenolic compounds. Energy Dispersive X-ray Spectroscopy (EDAX) showed carbon and oxygen as the principal elements, accompanied by trace minerals such as calcium, potassium, boron, magnesium, and zinc, signifying strong nutritional and therapeutic relevance. These findings suggest that C. limon and C. medica leaves are valuable sources of natural antioxidants, minerals, and phytochemicals suitable for developing functional foods, biodegradable edible products, and nutraceutical formulations. The valorization of citrus leaves supports sustainable waste management, promotes circular bioeconomy practices, and aligns with Sustainable Development Goal 12: Responsible Consumption and Production.