Determination of rutin and narcissin in marigold extract and topical formulations by liquid chromatography: applicability in skin penetration studies

Marigold Metabolites: Diversity and Separation Methods of Calendula Genus Phytochemicals from 1891 to 2022

Marigold (Calendula), an important asteraceous genus, has a history of many centuries of therapeutic use in traditional and officinal medicines all over the world. The scientific study of Calendula metabolites was initiated at the end of the 18th century and has been successfully performed for more than a century. The result is an investigation of five species (i.e., C. officinalis, C. arvensis, C. suffruticosa, C. stellata, and C. tripterocarpa) and the discovery of 656 metabolites (i.e., mono-, sesqui-, di-, and triterpenes, phenols, coumarins, hydroxycinnamates, flavonoids, fatty acids, carbohydrates, etc.), which are discussed in this review. The identified compounds were analyzed by various separation techniques as gas chromatography and liquid chromatography which are summarized here. Thus, the genus Calendula is still a high-demand plant-based medicine and a valuable bioactive agent, and research on it will continue for a long time.

In vitro growth-inhibitory effect of Brazilian plants extracts against Paenibacillus larvae and toxicity in bees

American foulbrood (AFB) is a serious worldwide spreading disease in bees caused by Paenibacillus larvae. Plants extracts are known to decrease or inhibit the growth of these bacteria. The purpose of this study was to evaluate the antimicrobial activity of Calendula. officinalis, Cariniana domestica, and Nasturtium officinale extracts against the P. larvae and to evaluate the toxicity of the extracts in bees. In vitro activity against P. larvae of the extracts was evaluated by micro dilution method and the minimal inhibitory concentrations (MICs) were also determined. The concentrations used in the toxicity test were established based on the MIC values and by the spraying application method. The P. larvae was susceptible to the evaluated crude extract of C. officinalis and N. officinale. To C. domestica, only the ethyl acetate (EtAc) fraction and n-butanol (BuOH) fractions had activity against P. larvae. Toxicity analysis in bees showed no toxicity for N. officinale crude extract and for C. domestica BuOH fraction during 15 days of treatment, however, some deaths of bees occurred during the first three days of treatment with C. officinalis and C. domestica EtAc fraction. The results with these species were firstly described and showed that N. officinale crude extract and C. domestica BuOH fraction both presented not toxic effects in the concentration tested by the spraying application method, and can be a useful alternative for treatment or prevention of AFB.

High performance thin layer chromatography (HPTLC) and high performance liquid chromatography (HPLC) for the qualitative and quantitative analysis of Calendula officinalis-advantages and limitations

Chromatography techniques such as HPTLC and HPLC are commonly used to produce a chemical fingerprint of a plant to allow identification and quantify the main constituents within the plant. The aims of this study were to compare HPTLC and HPLC, for qualitative and quantitative analysis of the major constituents of Calendula officinalis and to investigate the effect of different extraction techniques on the C. officinalis extract composition from different parts of the plant. The results found HPTLC to be effective for qualitative analysis, however, HPLC was found to be more accurate for quantitative analysis. A combination of the two methods may be useful in a quality control setting as it would allow rapid qualitative analysis of herbal material while maintaining accurate quantification of extract composition.

Efficacy of marigold extract-loaded formulations against UV-induced oxidative stress

The present study investigated the potential use of topical formulations containing marigold extract (ME) (Calendula officinalis extract) against ultraviolet (UV)B irradiation-induced skin damage. The physical and functional stabilities, as well as the skin penetration capacity, of the different topical formulations developed were evaluated. In addition, the in vivo capacity to prevent/treat the UVB irradiation-induced skin damage, in hairless mice, of the formulation with better skin penetration capacity was investigated. All of the formulations were physically and functionally stable. The gel formulation [Formulation 3 (F3)] was the most effective for the topical delivery of ME, which was detected as 0.21 μg/cm(2) of narcissin and as 0.07 μg/cm(2) of the rutin in the viable epidermis. This formulation was able to maintain glutathione reduced levels close to those of nonirradiated animals, but did not affect the gelatinase-9 and myeloperoxidase activities increased by exposure to UVB irradiation. In addition, F3 reduced the histological skin changes induced by UVB irradiation that appear as modifications of collagen fibrils. Therefore, the photoprotective effect in hairless mice achieved with the topical application of ME in gel formulation is most likely associated with a possible improvement in the collagen synthesis in the subepidermal connective tissue.