Flavonoids calendula

The flavonoid content of the tinctures of Calendula officinalis L., Passiflora incarnata L and Silybum marianum (L.) Gaertn. was investigated by HPLC-DAD and HPLC-MS. The anti-inflammatory effect, and the beneficial influence to treat hepatic injuries, tension... 

As its name suggests, supercritical fluid extraction (SEE) relies on the solubilizing properties of supercritical fluids. The lower viscosities and higher diffusion rates of supercritical fluids, when compared with those of liquids, make them ideal for the extraction of diffusion-controlled matrices, such as plant tissues. Advantages of the method are lower solvent consumption, controllable selectivity, and less thermal or chemical degradation than methods such as Soxhlet extraction. Numerous applications in the extraction of natural products have been reported, with supercritical carbon dioxide being the most widely used extraction solvent. However, to allow for the extraction of polar compounds such as flavonoids, polar solvents (like methanol) have to be added as modifiers. There is consequently a substantial reduction in selectivity. This explains why there are relatively few applications to polyphenols in the literature. Even with pressures of up to 689 bar and 20% modifier (usually methanol) in the extraction fluid, yields of polyphenolic compounds remain low, as shown for marigold Calendula officinalis, Asteraceae) and chamomile Matricaria recutita, Asteraceae). " ... 

Marked variations in the stability of 21 tinctures and 13 related singleentity plant compounds were noted (26). Bilia et al. (27) investigated the stability of 40% and 60% v/v tinctures of artichoke, SJW, calendula flower, milk thistle fruit, and passionflower. The investigation showed a very low thermal stability of the constituents from accelerated and long-term testing as determined by HPLC iode array detector and MS analyses. Stability was related both to the class of flavonoids and water content of the investigated tinctures. Shelf life at 25° C of the most stable tincture (passionflower 60% v/v) was about six months, whereas that of the milk thistle tinctures was only about three months. The stability of artichoke and... 

From the drug flos Calendulae Calendula officinalis L.), two flavonoids were isolated by bioassay-guided fractionation [226]. They showed potent antimicrobial activity against the following microorganisms Staphylococcus aureus, Klebsiella pneumoniae, Escherichia coli, Candida monosa and Sarcinia lutea. 

It is instructive to concentrate on the flavonoids, as these are of primary importance in qualitative assays of several HDs. Silica gel as stationary phase and ethyl acetate-ethyl methyl ketone-formic acid-water (50 30 10 10 by volume) as mobile phase is used in the analysis of flavonoids with C-glycosides (hawthorn, passion flower), and a mobile phase of ethyl acetate-formic acid-acetic acid-water (100 11 11 27 by volume) is used as the basic solvent for 0-glycosides (arnica, calendula, chamomille). Following spraying of the plates with 2-aminoethyldiphenyl-borinate (NTS, 1% in methanol) and subsequent treatment with poly(ethylene glycol) 4000 (PEG, 5% in ethanol), flavonoids display yellow to green fluorescence under UV irradiation at 365 nm. The frequently observed blue spots represent phenol... 

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