Anti-hyperlipidemic Potential of Vitex Donianaethanolextracts on Poloxamer 407 Induced Hyperlipidemic and Normal Rats

Anti-hyperlipidemic Potential of Vitex Donianaethanolextracts on Poloxamer 407 Induced Hyperlipidemic and Normal Rats

CHAPTER ONE

Objectives

1. To carry out the plant phytochemical screening, extracts total polyphenol and in vitro antioxidant activity.
2. To carry out in vivoantihyperlipidemic activity of the extractsand quantitative phytochemical of most potent extract.
3. To determine the effect of the extract onlipid profile andsomebiochemicalparameters of the hyperlipidemic and normal rats.
4. To determine the effect of the extract on lipid peroxidation and endogenous antioxidant enzymes in hyperlipidemic and normal rats.

CHAPTER TWO

LITERATURE REVIEW

Vitex Doniana

Vitex doniana is a deciduous tree, usually 4-8m high, occasionally up to 15m, with a heavy rounded crown. The bark is rough, pale brown or greyish-white, rather smooth with narrow vertical features. The bases of old trees have oblong scales.Leaves are opposite, glabrous, 14-34 cm long, usually with 5 leaflets on stalks 6-14 cm long. Leaflets distinctly stalked ovate, obovate, elliptic or oblong, entire, 8-22 cm long, 2-9 cm wide. Leaf tips rounded or emarginate, leaf bases cuneate, dark green above, pale greyish-green below, thickly leathery, with a few scattered stellate hairs on the upper surface, otherwise without hairs. Flower petals are white except on largest lobe, which are purple, in dense opposite and axillary cymes. Flowers small, blue or violet, 3-12 cm in diameter, only a few being open at a time. The fruit is oblong, about 3 cm long, green when young, turning purplish-black on ripening and with a starchy black pulp. Each fruit contains 1 hard, conical seed, 1.5-2 cm long, and 1-1.2 cm wide (Burkill, 2000).

CHAPTER THREE

MATERIALS AND METHODS 

Materials

Plant material

The Vitex doniana plants were harvested from its natural habitat at the Institute of Agricultural Research (IAR), Ahmadu Bello University (ABU), Zaria, Kaduna State in the month of April 2012, and authenticated at the Herbarium unit of the Department of Biological Sciences, Ahmadu Bello University, Zaria with a voucher number 1162.

CHAPTER FOUR

RESULTS

Phytochemical Constituent of Vitex Doniana

The result of the phytochemical screening of the plant is presented in Table 4.1. The result shows the presence of flavonoids, Terpenoids, Cardiac glycosides, alkaloids, saponins, and tanins in the leaves, stem bark and root bark ofVitex doniana. Terpenoids is present only in stem bark, Anthraquinone in leaves and root bark, whereas Steroids is present in the leaves and stem bark.

CHAPTER FIVE

DISCUSSION

Polyphenols are the major group of antioxidants that have generated a great interest among the scientists for the development of natural cure for cardiovascular diseases(Pietta, 2000). Antioxidant activity of a compound has been ascribed to the mechanism exerted by polyphenols (Anoosh and Fatemeh 2010). Recently, polyphenols have been considered powerful antioxidants in vitro and proven to be more potent antioxidants than Vitamin C, E and carotenoids (Rice-Evans, 1995; Rice-Evans, 1996). The inverse relationship between fruit and vegetable intake and the risk of oxidative stress associated diseases such as cardiovascular diseases has been partially ascribed to polyphenols (Hollman, 1999). Therefore, it was reasonable to determine the total polyphenol content of extracts from different part of the plant. The result shows that the ethanolic extracts had the highest polyphenol content when compared to the other extracts. Another remarkable observation is the high percentage yield shown by aqueous extracts. Aqueous extracts though gave a better yield of crude extract, but not good for polyphenol extraction. It extracted only the water-soluble bioactive compounds, moreover much other residual substances and impurities are present in the aqueous extract. It has been proposed that the antioxidant properties of polyphenols can be mediated by the following mechanisms; scavenging radical species such as ROS/RNS, suppressing ROS/RNS formation by inhibiting some enzymes or chelating trace metals involved in free radical production and upregulating or protecting antioxidant defense (Cotelle, 2001).

CHAPTER SIX

SUMMARY, CONCLUSIONS AND RECOMMENATIONS

Summary

• The phytochemical screening of Vitex donianaplant shows the presence of flavonoids, Cardiac glycosides, alkaloids, saponins and tanins in the leaves, stem bark and root bark.

• The percentage yield, total polyphenol and IC₅₀of the extracts show that in all the parts, aqueous extract had a higher percentage yield while ethanolic extract had the highest total polyphenol and least IC_5Ovalue when compared with the other extracts.

• The in vivo biological activity of the extracts shows that ethanolic extract has a higher percentage reduction of total cholesterol and triacylglycerol when compared to the other extracts.

• The quantitative phytochemical content of ethanolic extract shows that flavonoids and saponins were significantly (P<0.05) higher in leaves while Cardiac glycoside as highest in both leaves and stem bark. Alkaloids and tanins was significantly (P< 0.05) high in the root bark.

• All the parts have lowering effect on total cholesterol, triacylglycerol and low density lipoprotein-cholesterol with a concomitant increase in high density lipoprotein-cholesterol for hyperlipidemic ratsand no-significant (P>0.05) effects on normal rats.

• All the parts showed hepatopreventive effect as evident in the reduction of serum liver enzymes, total bilirubin, indirect bilirubin and increase in total protein and direct bilirubin for hyperlipidemic rats, and no-significant (P>0.05) effects on normal rats.

• All the parts enhanced kidney function parameters (creatinine and urea) as evident in the reduction of serum creatinine and urea for hyperlipidemic rats, and no-significant (P>0.05) effects on normal rats.

• All the parts increased packed cell volume of hyperlipidemic and normal rats.

• All the parts increased the body weight of hyperlipidemic treated rats and had no significant (P>0.05) effect on normal rats.

• All the parts possessed significant (P<0.05) antioxidant activity by reducing lipid peroxidation and significantly (P<0.05) increased the endogenous antioxidant enzymes in the liver and kidney of hyperlipidemic animals.

Conclusion

The result demonstrates that all the extracts (aqueous, 70% methanol, 70% ethanol and 70% acetone) of Vitex doniana (leaves, stem bark and root bark) possess antihyperlipidemic activity. The ethanolic leaves extract significantly (p<0.05) lowered TC, TAG, LDL-c and Log (TAG/HDL-c) which is the most accurate atherogenic risk predictor seems to have the highest antiatherogenic index. All the ethanolic extracts (leaves, stem bark and root bark) significantly (p<0.05) increased the SOD and CAT in the liver and kidney. The ethanolic stem bark significantly (p<0.05) reduced lipid peroxidation in both liver and kidney. This work thus provides the phytotherapeutic potential of leaves, stem bark and root bark of Vitex doniana that may be needed by scientists and researchers in nutraceutical industry.

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