MATERIALS AND METHODS

Plant material: Peperomia pellucida were harvested from a nearby bush close to the Biochemistry Department, University of Ibadan, Ibadan, Nigeria. They were identified and authenticated at Herbarium of the Department of Botany, University of Ibadan, Ibadan, Nigeria. The leaves were hand-picked and air-dried at room temperature. When dried, they were grounded to fine powder, using a laboratory mill and stored in air-tight containers for laboratory analysis. This study was carried out at the Biochemistry Department, University of Ibadan, Ibadan, Nigeria from January, 2008 too February, 2008. All analysis was carried out in triplicates.

Proximate analysis: Proximate analysis was carried out using the standard procedures of the AOAC (1997).

Mineral analysis: Mineral contents were determined on aliquots of the solutions of the ash of the dried leaf sample by UV/Visible and atomic absorption spectrophotometers (AOAC, 1997).

Phytochemical analysis: The qualitative phytochemical properties of the dried powdered sample were determined using standard methods described by Harborne (1993), Boham and Kocipai (1994), Ebrahimzadeh et al. (2008) and Nabavi et al. (2008).

Statistical analysis: Data were reported as mean of triplicates. Statistical analyses were carried out using SPSS for Windows, version 14.0 (SPSS Inc. Chicago, IL.USA).

RESULTS AND DISCUSSION

P. pellucida was observed to have high ash content (20.00%); the crude fiber content was higher (22.35%); with carbohydrate content the highest value (38.97%). The fat content was observed to be very low (1.08%) (Table 1).

The calcium content of P. pellucida was observed to be 1.82%; magnesium was observed to be 0.62%; while that of potassium was 0.59% (Table 2).

Table 1:	Proximate composition of Peperomia pellucida
Data are mean of triplicates

Table 2:	Mineral composition of Peperomia pellucida
Data are mean of triplicates

Table 3:	Phytochemical properties of Peperomia pellucida
+: Present; : Absent

Phytochemical screening of P. pellucida revealed the presence of alkaloids, tannins and cardenoloids. Anthraquinones was observed to be absen (Table 3).

Plants have played a significant role in maintaining human health and improving the quality of human life for thousands of years, and have served humans well as valuable components of food and medicines (Winston, 1999). The chemical properties of plants have been shown to be responsible for these nutritional and healing properties (Setchell and Cassidy, 1999). This study reports the chemical properties of P. pellucida.

The high crude fiber and carbohydrate contents compared favourably to studies by Aliyu et al. (2009) which reported high contents in Anisopus mannii (Asclepiadaceae). Food fibers have been shown to aid absorption of dietary minerals as well as reduce absorption of cholesterol (Aliyu et al., 2009). The observed ash content was higher than those reported on other medicinal plants such as Senna-siamea (Cassia Leaves): 17.93% (Alli Smith, 2009); Anisopus mannii (Asclepiadaceae): 10.36% (Aliyu et al., 2009); and B. falcatum: 4.68% (Adnan et al., 2010). It was however lower than those of F. tenacissima: 24.38 and V. officinalis: 27.91% (Adnan et al., 2010). The high ash content is an indication of the high mineral contents of the leaves of P. pellucida. The crude protein content compared favourably with and in most cases surpassed those reported for most medicinal plants (Abolaji et al., 2007; Aliyu et al., 2009; Adnan et al., 2010). This signifies the healing properties of P. pellucida as proteins are essential for the synthesis/repair of body tissues and as enzymes (Vaughan and Judd, 2003). The low fat content corroborates the findings of many authors which show that leafy vegetables are poor sources of lipids (Ejoh et al., 1996). Due to the general low level of crude fat in vegetable leaves and its high level of total unsaturated fatty acid, their consumption in large amounts would be beneficial to individuals suffering from overweight or obesity.

The health benefits of dietary minerals are well established. P. pellucida was observed to have a sodium concentration of 17.11 ppm which is rather too low compared to that observed by Adnan et al. (2010) on F. tenacissima (314 ppm) and L. angustifolia (375 ppm) respectively. The observed low sodium concentration makes the plant a potent herb in the management of hypertension, as high sodium content has been shown to contribute to hypertension in susceptible individuals, leading to increased calcium loss in urine (Wardlaw, 1999). The concentrations of the other micro mineral studied were observed to be very low compared to other medicinal plants (Adnan et al., 2010; Njoku and Akumefula, 2007).

The pharmacological and biochemical actions of phytochemicals have been widely reported by Amadi et al. (2006). Phytochemical screening of P. pellucida revealed the presence of alkaloids, cardenolides, saponins and tannins. Alkaloids have been reported to be the most efficient therapeutically significant phytochemical (Njoku and Akumefula, 2007). Stray (1998) reported that pure isolated alkaloids and their derivatives are basic medicinal agents because of their analgesic antispasmodic and bacterial properties. The hypocholesterolemic effect of saponins have been reported by Price et al. (1978), this may be attributed to its intra-luminal physicochemical interactions which reduces the uptake of certain nutrients including glucose and cholesterol (Alli Smith, 2009). The pesticidal activity of saponins has also been reported (Irvine, 1961). Saponin-glycosides are very toxic to cold-blooded organisms, but apparently not to mammals (Hostettmann and Marston, 1995; Hall and Walker, 1991), thus indicating the pesticidal potentials of P. pellucide. Tannins are widely classified as an antinutrient which affects protein digestibility and metal ion availability, but recent reports suggest that free or protein-complex condensed and hydrolysable tannins are more effective than small phenolics as antioxidants (Hagerman, 2002).

CONCLUSION

A result from this present study is an affirmation of the use of this plant in management of various ailments. The observed chemicals are responsible for its medicinal properties. The additive or synergistic action of these chemicals and their compounds at target sites associated with physiological process may be responsible for the beneficial effects exerted by P. pellucida.