BACKGROUND OF THE STUDY

Carica papaya is one of the most important tropical plants cultivated globally because of its nutritional, medicinal, and industrial values. The plant belongs to the family Caricaceae and is widely grown in tropical and subtropical regions, including Nigeria. Although the fruit is mainly consumed for food purposes, other parts of the plant such as seeds and leaves have attracted increasing scientific attention because of their rich phytochemical and essential oil contents. According to Tan, Tan, and Tan (2020), papaya seeds contain appreciable quantities of oil, fatty acids, tocopherols, carotenoids, phytosterols, and volatile compounds that can be utilized in pharmaceutical and industrial applications. Similarly, Yimyam et al. (2021) reported that papaya leaves possess several bioactive constituents including flavonoids, alkaloids, phenolics, and terpenoids responsible for their medicinal properties.

Essential oils (EOs) are natural volatile compounds obtained from plant materials and are widely used in food preservation, pharmaceuticals, cosmetics, agriculture, and traditional medicine. The quality and chemical composition of essential oils largely depend on the extraction method used. Azmir et al. (2013) explained that extraction techniques influence oil yield, stability, recovery efficiency, and preservation of active compounds. Conventional extraction methods such as hydrodistillation, steam distillation, Soxhlet extraction, and solvent extraction have traditionally been used for isolating essential oils from plant materials. However, these methods often involve prolonged extraction periods and high temperatures, which may result in degradation of heat-sensitive compounds.

Recent developments in extraction technologies have introduced modern techniques including ultrasound-assisted extraction (UAE), microwave-assisted extraction (MAE), and supercritical fluid extraction. According to Samaram et al. (2013), ultrasound-assisted extraction improved the recovery efficiency of papaya seed oil and produced variations in fatty acid composition when compared with conventional solvent extraction methods. The study further showed that extraction techniques significantly influence oil characteristics and chemical constituents.

Papaya seeds constitute approximately 15–20% of the total fruit weight and are generally discarded during fruit processing despite their valuable oil content. Tan et al. (2020) observed that papaya seed oil contains high levels of monounsaturated fatty acids, particularly oleic acid, making it suitable for industrial and nutritional applications. Likewise, Senrayan and Venkatachalam (2018) reported that different solvent extraction procedures produced variations in oil yield and physicochemical properties of papaya seed oil, suggesting that extraction conditions influence the chemical profile of the oil obtained.

Papaya leaves have also gained attention due to their medicinal importance in traditional healthcare practices. Several researchers have identified antioxidant, antimicrobial, anti-inflammatory, antimalarial, and anticancer properties associated with papaya leaf extracts. Aravind et al. (2013) stated that papaya leaves contain important phytochemicals such as alkaloids, saponins, flavonoids, tannins, and glycosides which contribute to their therapeutic effects. Furthermore, Fauziah and Wakidah (2019) reported that ultrasound extraction followed by chemical analysis revealed compounds such as neophytadiene, palmitic acid, and methyl linolenate in papaya leaves, indicating that extraction methods affect constituent recovery.

STATEMENT OF THE PROBLEM

The increasing demand for natural products, medicinal plant extracts, and essential oils has created interest in utilizing agricultural by-products and underexploited plant materials. Among these materials are Carica papaya seeds and leaves, which are usually discarded after fruit consumption despite their richness in bioactive compounds and essential oils. According to Tan et al. (2020), papaya seeds possess significant quantities of oil and valuable fatty acids, while Yimyam et al. (2021) reported that papaya leaves contain medicinal compounds with antioxidant and therapeutic properties.

Various extraction methods including hydrodistillation, solvent extraction, Soxhlet extraction, microwave-assisted extraction, and ultrasound-assisted extraction have been used for recovering essential oils and phytochemicals from plant materials. However, Azmir et al. (2013) explained that differences in extraction temperature, time, solvent type, and operational conditions may alter extraction efficiency and chemical composition of the extracted oils.