Table 1 showed the results of proximate analysis of the dry and fresh leaves of
Carica papaya. The results revealed that the dry and fresh leaves of
Carica papaya contained appreciable amounts of crude fat (8.750 and 8.850 % respectively), ash content (5.200 and 5.800 % respectively) and crude fibre (5.700 and 8.950 % respectively) but low amounts of crude protein (8.190 and 9.150 % respectively).
The present finding of crude protein (CP) value are lower than the reported values of 30.120 per cent
(Onyimonyi and Onu, 2009), 28.200 per cent
(Ebenebe et al., 2011) and 23.300 per cent
(Machoko et al., 2019) in papaya leaves, but close to the values of 8.900 and 8.630 per cent for unripe and ripe seeds of
Carica papaya respectively
(Akintunde et al., 2021 and
Kolu et al., 2021). This could be due to differences in soil, season, or location. Because the fresh and dry leaves of
Carica papaya are low in protein, it will need to be supplemented with protein if it is to be used in the diet of monogastric animals.
The crude fibre (CF) content of 5.700 and 8.950 percent of dry and fresh
Carica papaya leaves is higher than 5.600 percent revealed by
(Onyimonyi and Onu, 2009). But, it was lower than CF content found in unripe seed of
Carica papaya (23.200%) and sun-dried seeds of ripe
Carica papaya (28.300%)
(Akintunde et al., 2021; Kolu et al., 2021). Because of its low crude fiber content, this leaf could be used as a monogastric feed ingredient.
However, the ash percentage of 5.200 and 5.800 percent in dried and fresh
Carica papaya leaves is lower than that of some Nigerian leaves, such as sweet potato leaves, which have an ash value of 11 per cent
(Antia et al., 2006). It’s also lower than
(Akintunde et al., 2021 and
Kolu et al., 2021) reported for unripe (8.650%) and ripe (11.200%)
Carica papaya seeds. Its relatively high content reflects the mineral materials it has deposited.
Table 2 revealed some mineral content of pawpaw leaves. The dry and fresh leaves of
Carica papaya contained essential minerals: Calcium (1.200 and 1.0735%), Potassium (0.241 and 0.258%), Sodium (0.0245 and 0.001%) and Phosphorus (0.104 and 0.000%) respectively. The minerals contents of the dry and fresh leaves of
Carica papaya fruits are however significantly different (p<0.05) from each other.
The mineral composition revealed that
Carica papaya leaves are a significant source of mineral elements. According to the results of this study, the dry leaves of pawpaw, which are generally dismissed as nutritionally useless, contain higher levels of Ca, Na and P than the fresh leaves. When the usefulness of minerals like Ca, Mg, Na, K, Fe and Mn in the
Carica papaya leaves suggests that the leaves are useful in blood coagulation, the appropriate working of the heart and nervous system and the regular contraction of muscles, this result becomes extremely essential.
Magnesium and calcium help the body absorb phosphorus
(Claude and Paule, 1979). The potassium levels in the dried and fresh leaves, on the other hand, were nearly identical. Potassium is required for the muscular weakness associated with malaria, as well as for the slowing of vascular sclerosis. It aids in the fight against bacteria and aids in the cleansing of the digestive tract. Sodium aids in water metabolism, digestion, assimilation and osmosis, as well as cleansing the digestive system, combating stomach acidity and alkalinizing the blood
(Claude and Paule, 1979). It is for this reason that the brown pawpaw leaf is employed as a cleaner in herbal remedies
(Atta, 1999).
Table 3 showed that the dry and fresh leaves of
Carica papaya fruits contained vitamin B1 (0.282 and 0.620 mg/100 g), vitamin B2 (0.0345 and 0.0695 mg/100 g), vitamin C (19.700 and 26.900 mg/100 g) and vitamin E (48.195 and 31.675 mg/100 g). The fresh leaf samples however had significantly higher (p<0.05) vitamin C and B2.
When comparing the fresh and dried leaves of
Carica papaya, the fresh leaves have higher quantities of vitamin C, B1 and B2. The vitamin E content of dried leaves (48.195 mg/100g) was higher than that of fresh leaves (31.675 mg/100g). Ascorbic acid deficiency is linked to joint aches, a defect in skeletal calcification, anemia and scurvy hemorrhage from the mouth and gastrointestinal tract
(Hunt et al., 1980). This function of ascorbic acid explains why it is required for normal wound healing. Ascorbic acid also has the intriguing ability as an antioxidant, to prevent or at least reduce the production of carcinogenic chemicals from dietary material
(Hunt et al., 1980). Other vitamins are necessary for biological metabolism, even if they are only in trace amounts
(Njoku and Akumefula, 2007). Because of the presence of vitamins C and E, the leaves are also a promising for countering oxidative stress, particularly in broiler chicken production.
The phytochemical analysis of the leaves (Table 4) showed that the leaves contained flavonoids, alkaloids, saponin, tannin, phenols, terpenes and steroid. When compared to fresh leaves, the dry leaves had a larger amount of saponin, phenol, terpene, steroid and flavonoids content. The same amount (0.003 mg/100 g) of flavonoid content was observed in dried and fresh leaves in this investigation.
Both the dry (0.269 mg/100g) and fresh (0.240 mg/100g) leaves contained comparatively similar amounts of alkaloid. The most effective therapeutically significant plant ingredient is alkaloids. Because of their analgesic, antispasmodic and antibacterial characteristics, pure isolated alkaloids and synthetic derivatives are utilized as fundamental medical agents
(Stray, 1998). When given to animals, they have noticeable physiological effects.
Due to the fact that saponins are cytotoxic, the presence of saponins supports the notion that pawpaw leaf has cytotoxic effects such as intestinal permealization
(Okwu and Okwu, 2004). It also imparts a bitter flavor to the leaves. Saponin interacts with sex hormones such as oxytocin. Oxytocin is a sex hormone that regulates the commencement of labor and the subsequent release of milk in women
(Okwu and Okwu, 2004). Saponins also have an expectorant effect, which is mediated by the stimulation of an upper digestive tract reflex
(David, 1983).
The dry and fresh leaves of pawpaw as observed from this study contain low levels of tannin (0.004 and 0.005 mg/100 g respectively). The values are lower than the values of 52.920 and 66.500 mg/100 g for sun-dried and oven-dried seeds of ripe
Carica papaya respectively as reported by
Kolu et al. (2021). The values for tannin from the leaves (dry and fresh) in the present study was very much lower than the unripe seeds of
Carica papaya (84.120 mg/100 g) as reported by
Akintunde et al. (2021) but closer to the 0.09% oberved in
Moringa oleifera seeds
(Akintunde and Toye, 2014). The low levels of tannin for both the dry and fresh leaves of
Carica papaya suggest the safety of its inclusion in monogastric animal’s nutrition.
The dry (0.316 mg/100 g) leaves had a substantially higher phenolic content than the fresh (0.169 mg/100g) leaves. When compared to flavonoids and coumarin compounds, the primary chemicals found in
C. papaya leaves are phenolic acids and trace levels of chlorogenic acid, according to
(Canini et al., 2007). The existence of such phenolic and coumarin chemicals in
C. papaya leaves could partially explain the plant’s pharmacological characteristics. However, this study reveals that both fresh and dry leaves of
Carica papaya contain significant amounts of phenols, implying that they could be used as ethno-medicinal plants.
The dry (0.212 mg/100 g) pawpaw leaves have more terpenes than the fresh (0.001 mg/100 g) leaves. Terpenoids have medical qualities such as hepaticidal, anti-microbial, or diuretic (
e.g., glycyrrhizin)
(Dudareva et al., 2004). In their interaction with free radicals, terpenes have a particular antioxidant function.
Pawpaw leaves, both dry and fresh, contain steroids. Steroids are most known for their ability to affect lipid metabolism
(Bartnikowska, 2009). Phytosterol, a type of steroid, has anti-inflammatory properties as well as inhibiting cholesterol absorption in the intestine
(Navarro et al., 2001; Awad et al., 2004). Steroids are also utilized to make medications and a variety of sex hormones. This could explain why the plant is used to treat urogenital infections and urethral discharge
(Okoli et al., 2008), as well as false labor and threatening abortion
(Orlu and Obulor, 2014). Steroids are also known for their antibacterial properties, which are linked to membrane lipids and cause leaking from liposomes
(Epand et al., 2007).