Abstracts of papers and posters 19th LOF-Symposium on Pharmacognosy and Natural Products Chemistry (original) (raw)

The active constituents of herbs and their plant chemistry, extraction and identification methods

Journal of chemical and pharmaceutical research, 2016

The active constituents of plants have only relatively recently been isolated. The active constituents in plants are the chemicals that have a medicinal effect on the body. These are the active ingredients of the plant, the chemicals that have a marked, definable physiological and therefore, possibly medical activity upon the body. These constituents and their actions within the body are also referred to as their pharmacology. They have been divided into 16 main groups: Alkaloids, Anthocyanins, Anthraquinones, Cardiac Glycosides, Coumarins, Cyanogenic Glycosides, Flavonoids, Glucosilinates, Phenols, Saponins, and Tannins

Investigation of the pharmaceutical and pharmacological equivalence of different Hawthorn extracts

Phytomedicine, 2003

Seven Hawthorn extracts were tested in isolated guinea pig aorta rings. The effect on noradrenaline-(10 µM) induced contraction was investigated. The extracts were prepared using ethanol (40 to 70% v/v), methanol (40 to 70% v/v), and water as the extraction solvents. The aqueous-alcoholic extracts displayed similar spectra of constituents. They were characterised by similar procyanidin, flavonoid, total vitexin and total phenols content and by similar TLC fingerprint chromatograms. The aqueous extract, however, showed a different fingerprint and a noticeably lower concentration of procyanidins, flavonoids and total phenols but a similar total vitexin content. All 7 extracts had a relaxant effect on the aorta precontracted by noradrenaline and led to relaxations to 44 until 29% of the initial values. The EC 50 values of the aqueous-alcoholic extracts varied between 4.16 and 9.8 mg/l. The aqueous extract produced a similarly strong maximal relaxation as the other extracts, but the EC 50 , at 22.39 mg/l, was markedly higher. The results show that Hawthorn extracts with comparable quality profiles were obtained by using aqueous-alcoholic extraction solvents (40 to 70% ethanol or methanol). The extracts exerted comparable pharmacological effects. When using water as the extraction solvent, both, the spectrum of constituents and the pharmacological effect, deviated remarkably. It is thus possible to obtain bioequivalent extracts with comparable effect profiles by using 40 to 70% ethanol or methanol as the extraction solvent.

Phytochemical analysis of the selected five plant extracts

Chemistry and Materials Research, 2013

Herbal medicine is still the mainstay of about 75-80% of the whole population, and the major part of traditional therapy involves the use of plant extracts and their active constituents. Plants were collected, identified, dried then extracted using hexane, Dichloromethane/methanol and water. Identification assays to test the presence of various chemical constituents were carried out. The five plants were: Sonchus luxurians, Ocimum americanum, Bridelia micrantha, Croton megalocarpus and Aloe secundiflora. The Phytochemical screening of the compounds present in the plant extracts were; alkaloid, glycosides, Saponins, reducing sugar, Steroid, Flavones and Catecholics. The most common compound in all the plant extracts was Catecholics. Steroids are used in medicine to treat many diseases. The Plant extracts can be possible candidates for drug development.

Chemical analysis and quality control of Ginkgo biloba leaves, extracts, and phytopharmaceuticals

Journal of Chromatography A, 2009

The chemical analysis and quality control of Ginkgo leaves, extracts, phytopharmaceuticals and some herbal supplements is comprehensively reviewed. The review is an update of a similar, earlier review in this journal [T.A. van Beek, J. Chromatogr. A 967 (2002) 21-55]. Since 2001 over 3000 papers on Ginkgo biloba have appeared, and about 400 of them pertain to chemical analysis in a broad sense and are cited herein. The more important ones are discussed and, where relevant, compared with the best methods published prior to 2002. In the same period over 2500 patents were filed on Ginkgo and the very few related to analysis are mentioned as well. Important constituents include terpene trilactones, i.e. ginkgolide A, B, C, J and bilobalide, flavonol glycosides, biflavones, proanthocyanidins, alkylphenols, simple phenolic acids, 6-hydroxykynurenic acid, 4-O-methylpyridoxine and polyprenols. In the most common so-called "standardised" Ginkgo extracts and phytopharmaceuticals several of these classes are no longer present. About 130 new papers deal with the analysis of the terpene trilactones. They are mostly extracted with methanol or water or mixtures thereof. Supercritical fluid extraction and pressurised water extraction are also possible. Sample clean-up is mostly by liquid-liquid extraction with ethyl acetate although no sample clean-up at all in combination with LC/MS/MS is gaining in importance. Separation and detection can be routinely carried out by RP-HPLC with ELSD, RI or MS, or by GC/FID or GC/MS after silylation. Hydrolysis followed by LC/MS allows the simultaneous analysis of terpene trilactones and flavonol aglycones. No quantitative procedure for all major flavonol glycosides has yet been published because they are not commercially available. The quantitation of a few available glycosides has been carried out but does not serve a real purpose. After acidic hydrolysis to the aglycones quercetin, kaempferol and isorhamnetin and separation by HPLC, quantitation is straightforward and yields by recalculation an estimation of the original total flavonol glycoside content. A profile of the genuine flavonol glycosides can detect poor storage or adulteration. Although the toxicity of Ginkgo alkylphenols upon oral administration has never been undoubtedly proven, most suppliers limit their content in extracts to 5 ppm and dozens of papers on their analysis were published. One procedure in which a methanolic extract is directly injected on a C8 HPLC column appears superior in terms of sensitivity (<5 ppm), separation, simplicity and validation and will be incorporated in the European Pharmacopoeia. Alternatively GC/MS and ELISA methods can be used. A sharp contrast to the plethora of papers on terpene trilactones, flavonol glycosides, and ginkgolic acids forms the low number of papers on biflavones, proanthocyanidins, simple phenolics, simple acids, and other constituents that make up the remaining 70% of Ginkgo standardised extracts. More research in this direction is clearly needed. For the analysis of Ginkgo proanthocyanidins (7%) for instance, no reliable assays are yet existing. Finally the growing literature on pharmacokinetic and fingerprinting studies of Ginkgo is briefly summarised.

PHYTOCHEMICAL SCREENING OF PLANT EXTRACTS

An overview on some standard procedures on how to screen for the presence of biometabolites (phytochemicals) in plants extracts. The procedures are standard, universally accepted by s. Most of these procedures can also be found in some world leading journals, such as international journals of Microbiology, pharmaceutical science as well as journals of medicine. These are sets of standard procedures for both qualitative and quantitative analysis for the presence of saponins, amino acids, flavonoids, reducing sugars, tannins, steroids and tritepenoid.

Quality control analyses for Ginkgo extracts require analysis of intact flavonol glycosides

Journal of Food and Drug Analysis, 2020

Ten commercial standardized Ginkgo biloba extracts were examined for flavonol glycoside and terpene lactone content. All samples arrived with certificates of analysis stating that the extracts were standardized Ginkgo biloba leaf extract and that they contained a minimum of 24% total flavonol glycosides and 6% terpene lactones. Samples were analyzed for total flavonol glycosides using a method involving acid hydrolysis and subsequent quantification of the flavonol aglycones by HPLC coupled with UV diode array absorbance detection. Analysis of intact flavonol glycosides and terpene lactones was accomplished using HPLC coupled with UV diode array detection and electrospray mass spectrometric detection. Of the ten standardized extracts eight samples provided chromatograms and chemical values characteristic of previously published analyses of ginkgo leaf extracts. One sample provided analyses that suggested that the extract had been adulterated with rutin in order to elevate total flavonol glycoside levels. Another sample indicated that it was not an extract of Ginkgo biloba leaf at all. Adulteration with rutin was not strongly evident when the acid hydrolysis method was used to analyze the sample for total flavonol glycosides. However, this particular adulteration was easily evident when analyzing the samples for characteristic intact flavonol glycosides. This work demonstrates the need for extensive quality control analyses for herbal products and that the analysis of intact characteristic compounds provides a reliable method for detecting adulteration.

Phytochemical Constituents of some Medicinal Plants

In this study, five medicinal plants materials were analysed in order to investigate the presence of phytochemicals and to determine amount of tannin, glucosides, hydrogen cyanide, steroid, soluble carbohydrate, flavonoid and alkaloid in the five selected medicinal plants. The five test plant materials were Azadirachta indica leaves, Garcinia cola seeds, Zingiber officinale stem, Gongronema latifolia leaves and Carica papaya leaves. Phytochemical analysis done on Azadirachta indica A Juss, Garcinia cola Henkel, Zingiber officinale Rose, Gongronema latifolia L. and Carica papaya L. revealed the presence of tannin, soluble carbohydrate, hydrogen cyanide, steroids, flavonoids, alkaloids as well as glucosides in all the extracts tested. It also showed the levels of tannin, soluble carbohydrate, hydrogen cyanide, steroids, flavonoids, alkaloids and glucosides in the