Analytical, biological, pharmacokinetic and stability studies of piper sarmentosum roxb. extracts and selected studies of orthosiphon stamineus benth. extracts

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Date
2008
Authors
Hussain, Khalid
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Abstract
The study aimed to perform analytical and biological activity studies on root, stem, leaf and fruit of Piper sarmentosum and leaves of Orthosiphom stamineus, pharmacokinetic and stability studies on ethanol extract of fruit of Piper sarmentosum. Powdered material of different parts of Piper sarmentosum was extracted using ethanol and water while leaves were also extracted sequentially using petroleum ether, chloroform and methanol. Leaves of Orthosiphom stamineus were extracted with methanol and few prepared extracts were obtained from different sources. The extracts of both the plants were analyzed qualitatively and quantitatively using Fourier Transform Infrared (FTIR) and ultraviolet/visible (UV Nis) spectroscopy, high performance thin layer chromatography (HPTLC) and high performance liquid chromatography (HPLC). Aqueous and ethanol extracts of different parts of Piper sarmentosum were investigated for in vitro antioxidant activity and the extracts having good activity namely fruit and leaf ethanol extracts were evaluated for in vivo antioxidant and hepatoprotective activity using CCL. induced oxidative stress model. Sequential extracts of Piper sarmentosum leaf and fractions of the methanol extract, aqueous extract of Orthosiphom stamineus and its fractions were investigated for antiangiogenic and interaction studies. Ethanol extract of the fruit of Piper sarmentosum was investigated for pharmacokinetic and accelerated stability studies using pellitorine, sarmentine and sarmentosine as markers. Qualitative analysis indicated the presence of flavonoids and alkaloids in ethanol extracts of different parts of Piper sarmentosum while flavonoids and triterpenes in extracts of Orthosiphom stamineus. Quantitative analysis of different extracts of Piper sarmentosum by HPTLC indicated varying amaunts of rutin (0.0004-0.0109 mg/g) and naringenin (0.010-0.659 mg/g). The HPTLC analysis of different extracts of Orthosiphon stamineus indicated varying amaunts of betulinic acid (0.013-0.124 mg/g) and sinensitin (0.470-1.335 mg/g). A new HPLC method was developed, validated and applied for the simultaneous quantification of rutin and flavonone in Piper sarmentosum extracts which indicated varying amaunt of rutin ranging 0.20-5.02 mg/g and flavonone 0.32- 15.32 mg/g. Another HPLC method was developed, validated and applied for the simultaneous quantification of pellitorine, sarmentine and sarmentosine in Piper sarmentosum extracts which indicated varying amaunts of pellitorine ranging 0.043- 6.820 mg/g, sarmentine 0.006-0.420 mg/g and sarmentosine 0.005-0.120 mg/g. A previously used HPLC method for the quantification of betulinic acid was improved, validated and applied to analyse different extracts of Orthosiphon stamineus which exhibited varying amaunts ofbetulinic acid ranging 2.76-9.50 mg/g. Ethanol extracts of the fruit and leaf of Piper sarmentosum exhibited good in vitro antioxidant activities in DPPH model with ICso at 25.87 and 23.66 ~g/mL, respectively. Both the extracts have also shown good activity in 13-carotene linoleate model. The antioxidant activity of the extracts was found to be correlated with total content ofpolyphenolics, flavonoids and amides (P < 0.05). Acute oral toxicity studies of the fruit and leaf ethanol extracts of Piper sarmentosum indicated median lethal dose (LD5o) above 2000 mg/kg in rats. The extracts of both the parts were investigated for in vivo antioxidant and hepatoprotective activities in two dose levels 250 and 500 mg/kg. The pretreated groups exhibited significant preservation of antioxidant activity and liver function markers as compared to negative control (CC4) group (P < 0.05). Chloroform extract of the leaf of Piper sarmentosum and n-hexane fraction of aqueous extract of Orthosiphon stamineus exhibited 100 and 80% antiangiogenic activity with IC50 at 45 f.lg/mL and IC50 at 45 f.lg/mL, respectively. Amides isolated from the fruit of Piper sarmentosum, pellitorine, sarmentine and sarmentosine, exhibited 30 % antiangiogenic activity while the isolated compounds from the nhexane fraction of Orthosiphon stamineus, betulinic, oleanolic and ursolic acids, exhibited 100% antiangiogenic activity. In cytotoxicity studies, the chloroform extract and the n-hexane fraction have shown-- IC50 at 76.24 and 80 f.lg/mL, respectively, which are higher as compared to ICso of antiangiogenesis. Chloroform and ethyl acetate fractions of the leaf methanol extract of Piper sarmentosum have shown antimycobacterial activity with minimum inhibitory concentration (MIC) 3.12 f.lg/mL while n-hexane fraction of aqueous extract of Orthosiphon stamineus has shown the activity MIC 3.12 f.lg/mL. In interaction studies, the extracts and the fraction of both the plants have not shown any interaction with isoniazid because fractional inhibitory concentration index (FICI) was found to be > 0.5. A new HPLC method was developed, validated and applied for the simultaneous determination ofpellitorine, sarmentine and sarmentosine from plasma, urine, fecal matter and tissues. In pharmacokinetic studies of the fruit ethanol extract of Piper sarmentosum in rats, pellitorine and sarmentine showed good oral bioavailability while sarmentosine was not absorbed orally and excreted unchanged in feces. Pellitorine and sarmentine exhibited different tissue affinities and were excreted in urine as metabolites. In accelerated stability studies, estimated shelf life (19o) of pellitorine, sarmentine and sarmentosine was approximately 16 months at 25 °C. The markers followed the zero order reaction and their stability was found to be decreasing at high temperature and relative humidity (RH). The results of the study indicates that the developed HPLC methods are simple, easy to perform and can be applied for standardization. Extracts of Piper sarmentosum have promising antioxidant and hepatoprotective activity. Chloroform extracts of Piper sarmentosum and n-hexane fraction of aqueous extract of Orthosiphon stamineus have promising antiangiogenic activity. The extracts of both the plants have no interaction with isoniazid.
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Pharmacokinetic , Piper sarmentosum roxb. , Orthosiphon stamineus benth.
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