Phytochemicals, Antioxidants and Toxicological Properties of Methanol Extract of Securidaca Longepedunculata

Phytochemicals, Antioxidants and Toxicological Properties of Methanol Extract of Securidaca Longepedunculata.

ABSTRACT

One of the problems associated with medicinal plants in Nigeria is paucity of information on the phytochemistry and toxicity of some of these plants.

The study aimed at revealing a range of phytochemicals in the plant, which are physiologically potent in ameliorating several diseases.

The potent secondary metabolites in the leaves of this plant Securidaca longepedunculata , were extracted and their antioxidant and toxicological potentials were evaluated using in vitro methods and albino rats as the models.

The results showed that methanol extract scavenged 1, 1- diphenyl-2- picrylhydrazyl radical (DPPH. ) in a concentration dependent manner with a correlation coefficient (R2 ) of 0.976, indicating antioxidant activity with effective concentration that inhibits 50 percent of the radicals (EC50) of 90.02±0.2 µg/ml compared to ascorbic acid standard with EC50 of 98.01±0.2 µg/ml.

Superoxide radical scavenging activity was concentration dependent with an EC50 of 350.11±0.42 µg/ml compared with ascorbic acid standard with EC50 of 812.97±0.97 µg/ml.

The extract, also showed hydroxyl radical scavenging activity with an EC50 of 83.74±0.02µg/ml compared to α- tocopherol standard with EC50 of 54.16±0.01 µg/ml. There was an inverse correlation between the percentage inhibition and concentration with R2 of -0.958.

The methanol extract, also scavenged nitric oxide radical in a concentration dependent manner with 500 µg/ml being more effective than 500 µg/ml of ascorbic acid standard.

Comparison of the anti-radical power (ARP) of DPPH. (0.011), superoxide radical (0.003) and hydroxyl radical (0.012) of the extract revealed that the ARP of the extract against hydroxyl radical was most efficacious.

The antioxidant vitamin contents of the extract showed that vitamin C was significantly high (p< 0.05), (4.62±0.14 mg/100g) when compared to vitamin A (0.902±0.05 µg/g) and vitamin E (1.474±0.01 mg/100g).

The 100, 200 and 500 mg/kg bw fed to rats significantly increased (p< 0.05) catalase activity, while in weeks two and three the catalase activity decreased significantly (p< 0.05).

The extract solution showed a maximum absorption at wavelength (lambdamax) of 285nm-thus indicating that subsequent investigations using the extract would be better at UV region in absorption spectra.

There was no death in the mean lethal dose (LD50) investigation. The aspartate aminotransferase (AST) showed a significant decrease (p< 0.05) in week one and an increase in other weeks.

The alanine aminotransferase (ALT) showed a significant decrease (p< 0.05), in weeks one, three and four while week two showed a non-significant increase (p> 0.05). The serum alkaline phosphatase (ALP) showed a significant (P £ 0.05) decrease in activity in all the groups at weeks one and two.

INTRODUCTION

Phytomedicinal research of indigenous plant parts is presently gaining more grounds than ever as the majority of people are now patronizing herbal medicinal treatment which is considered to be more easily accessible and cheaper than orthodox medical treatment (Ajiboye et al., 2010).

The usefulness of medicinal plants is directly linked to the wide range of chemical compounds synthesized in various biochemical pathways; which are classified as secondary metabolites(Ameyawand Duker-Eshun, 2009).

The medicinal value of these plants lies in some chemical substances that produce a definite physiological action on the human body (Edoga et al., 2005; Lavanya et al., 2007).

Antioxidants can delay or inhibit the oxidation of lipids, proteins, DNA or other biomolecules by inhibiting the initiation or propagation of oxidative chain reaction, (Awah et al., 2010), thereby preventing the untimely death of a cell and some ailments.

The measurement of enzyme activities in the body fluid aids the diagnosis of assault on organs and tissues and also assists the determination of the toxicity of chemical compounds or drugs (Ajiboye et al., 2010).

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