Estimation of yohimbine base in complex mixtures by quantitative HPTLC application

The indole alkaloid Yohimbine has been used for over two centuries in the treatment of erectly dysfunction. Several formulations containing yohimbine salts, yohimbe bark power or extract are marketed worldwide. Determination of the amount of yohimbine in such formulation is a challenging task due to their complex nature. Extraction followed by acid-base purification resulted in a relatively pure alkaloids containing fractions. The exact amounts of yohimbine free base in different formulations were determined by densitometric HPTLC validated methods using silica gel TLC plates. Standard curve for yohimbine was generated using yohimbine hydrochloride subjected to the same acid-base treatment as the used samples. All formulations found to contain yohimbine though some with less concentration than the labeled amount

Densitometric HPTLC method for qualitative, quantitative analysis and stability study of coenzyme Q10 in Pharmaceutical formulations utilizing normal and reversed-phase silica gel plates

Two simple, preciseand stability-indicating densitometric HPTLC method were developed and validated for qualitative and quantitative analysis of Coenzyme Q10in pharmaceutical formulations using normal-phase [Method I] and reversed phase [Method II] silica gel TLC plates. Both methods were developed and validated with 10x20cm glassbacked plates coated with 0.2mm layers of either silica gel 60 F[254] [E-Merck, Germany] using hexane-ethyl acetate [8.5:1.5v/v] as developing system [Method I] or RP-18 silica gel 60 F[254] [E-Merck, Germany] using methanol-acetone [4:6v/v] as mobile phase [Method II]. Both analyses were scanned with a densitometer at 282 nm. Linearity was found in the ranges 50-800ng/spot [r[2]=0.9989] and 50-800ng/spot [r[2]=0.9987] for Method I and Method II respectively. Stability of Coenzyme Q10 was explored by the two methods using acid, base, hydrogen peroxide, temperature and different solvents. Due to the efficiency of the method in separating Coenzyme Q10 from other ingredients including its degradation products, it can be applied for quality control, standardization of different pharmaceutical formulations and stability study

Antioxidant study of flavonoid derivatives from the aerial parts of Rhus natalensis growing in Saudi Arabia

Phytochemical study of the CH[2]Cl[2] soluble fraction of the aerial parts of R. natalensis resulted in the isolation and identification of six flavonoid derivatives, beta -amyrin and beta -sitosterol glucoside [daucosterol]. The isolated compounds were identified utilizing physical, chemical and different spectral methods including UV, 1D- 2D-NMR and MS. The compounds were identified as four flavanones; 7-O-methyl hesperetin [1], 7-O-methyl naringenin [4], [-]- homoeriodictyol [eriodictyonone] [5], eriodictyol-7-methyl ether [6] and two flavones; 7-O-methyl isokaemferide [2] and genkwanin [3]. The isolated compounds as well as some available standards representing structurally similar flavones and flavanones were used to study their antioxidant potential using DPPH and try to explore the impact of structures on the antioxidant activity. In other assays flavanones were less active than flavones as antioxidant due to lack of the C-4 carbonyl group in conjugation with 2,3-double bond. However, in DPPH assay based on the ability of molecules to donate hydrogen flavanones were found more active than flavones

Quantitative estimation of pulegone in Mentha longifolia growing in Saudi Arabia. is it safe to use?

Our TLC study of the volatile oil isolated from Mentha longifolia showed a major UV active spot with higher Rf value than menthol. Based on the fact that the components of the oil from same plant differ quantitatively due to environmental conditions, the major spot was isolated using different chromatographic techniques and identified by spectroscopic means as pulegone. The presence of pulegone in M. longifolia, a plant widely used in Saudi Arabia, raised a hot debate due to its known toxicity. The Scientific Committee on Food, Health and Consumer Protection Directorate-General, European Commission set a limit for the presence of pulegone in foodstuffs and beverages. In this paper we attempted to determine the exact amount of pulegone in different extracts, volatile oil as well as tea flavoured with M. longifolia [Habak] by densitometric HPTLC validated methods using normal phase [Method I] and reverse phase [Method II] TLC plates. The study indicated that the style of use of Habak in Saudi Arabia resulted in much less amount of pulegone than the allowed limit

Quantitative estimation of hesperidin by HPTLC in different varieties of citrus peels

<p><b>OBJECTIVE</b>To develop a simple, selective, sensitive and accurate high-performance thin layer chromatography (HPTLC) method to determine the quantity of hesperidin in different varieties of citrus fruits.</p><p><b>METHODS</b>The method was carried out in aluminum-backed silica gel 60 F254 plates with ethyl acetate-methanol-water 15:3:2 (%, v/v) as mobile phase.</p><p><b>RESULTS</b>A compact band was obtained for hesperidin at Rf value of (0.40±0.04). The calibration plot was linear in the range of 100-800 ng/spot of hesperidin and the correlation coefficient of 0.998 6 was indicative of good linear dependence of peak area on concentration. Limit of detection (8.87 ng/spot), limit of quantification (23.21 ng/spot), accuracy (less than 2%) and recovery (ranging from 98.55-99.38) were found satisfactory.</p><p><b>CONCLUSIONS</b>The method developed can be used for routine analysis of hesperidin in crude drug as well as in herbal and pharmaceutical dosage form containing citrus fruits as an ingredient.</p>

Theoretical and experimental study on lipophilicity and wound healing activity of ginger compounds

<p><b>OBJECTIVE</b>To correlate the chromatographic and computational method to calculate lipophilicity of selected ginger compounds and to observe the effects of log P on wound healing.</p><p><b>METHODS</b>Mixtures of acetonitrile and water with acetonitrile content between 95% and 50% v/v in 5% increments were kept separately in 10 different chromatographic chambers, saturated with solvent for 2 h. Spots were observed under UV light at λ=254 nm p-anisaldehyde used as a spraying reagent. Theoretical calculation was done using the Alogps 2.1 online program at www.vcclab.org/lab/alogps. For percentage wound contraction, five groups of animal (mice) (25-30 g) of either sex were selected. Wound were created on dorsal surface of animals using toothed forceps, scalpel and pointed scissors. The wound areas were calculated using vernier caliper. After making wound mice were orally administered 35 mg/kg 6-shogoal, 6-gingerol, 8-gingerol and 10-gingerol respectively. Group E as the control group received tap water.</p><p><b>RESULTS</b>The lipophilicity values determined in thin layer chromatography were correlated with the theoretically calculated various log P by linear regression analysis. Significant correlations were found between log P values calculated by software program and the experimental reversed-phase thin-layer chromatography data. Order of wound healing property of ginger compounds is directly dependent on lipophilicity i.e. more lipophilic compound has highest activity.</p><p><b>CONCLUSIONS</b>Experimentally determined lipophilicity (R MO) values were correlated with log P determined by software's and found satisfactory. Lipophilicity (R MO) is a useful parameter for the determination and prediction of biological activity of ginger compounds.</p>

Densitometric HPTLC analysis of 8-gingerol in Zingiber officinale extract and ginger-containing dietary supplements, teas and commercial creams

Objective: To develop and validate a simple, accurate HPTLC method for the analysis of 8-gingerol and to determine the quantity of 8-gingerol in Zingiber officinale extract and ginger-containing dietary supplements, teas and commercial creams. Methods:The analysis was performed on 10×20 cm aluminium-backed plates coated with 0.2 mm layers of silica gel 60 F254 (E-Merck, Germany) with n-hexane: ethyl acetate 60: 40 (v/v) as mobile phase. Camag TLC Scanner III was used for the UV densitometric scanning at 569. Results:This system was found to give a compact spot of 8-gingerol at retention factor (Rf) value of (0.39±0.04) and linearity was found in the ranges 50-500 ng/spot (r2=0.9987). Limit of detection (12.76 ng/spot), limit of quantification (26.32 ng/spot), accuracy (less than 2 %) and recovery (ranging from 98.22-99.20) were found satisfactory. Conclusions:The HPTLC method developed for quantification of 8-gingerol was found to be simple, accurate, reproducible, sensitive and is applicable to the analysis of 8-gingerol in Zingiber officinale extract and ginger-containing dietary supplements, teas and commercial creams.