Bioactivities of Alchemilla mollis, Alchemilla persica and Their Active Constituents

Abstract The aim of this study was to determine antimicrobial activities of Alchemilla mollis, Alchemilla persica as well as ellagic acid and miquelianin against Staphylococcus aureus, Enterococcus faecalis, Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa, Candida albicans by using microbroth dilution method and anti-inflammatory activity by using human red blood cell (HRBC) membrane stabilization method. Microbroth dilution method was used to determine the antimicrobial activities. Extracts possessed activity having MIC values of 2.5-5-10mg/ mL, compounds possessed activity having MIC values of 1.25-2.5-4-5mg/mL. A.mollis aerial parts displayed the highest anti-inflammatory activity (IC50=1.22±0.07mg/mL). Ellagic acid and miquelianin were also determined as anti-inflammatory agents with 0.57±0.01mg/mL and 1.23±0.02mg/mL IC50 values, respectively. Total phenolic content and tannin content of the A.mollis and A.persica were determined as 357.00±75.80mg, 282.50±28.70mg PGE/g plant material and 18.02%, 18.63% respectively according to the method described by European Pharmacopoeia. Ellagic acid, miquelianin and catechin were analyzed by HPLC. The highest catechin content was detected in A.persica roots (6.69±0.05g/100g plant material). A.mollis aerial parts contain higher miquelianin (0.39±0.02g/plant material) and ellagic acid (1.56±0.01g/ plant material) than A.persica.

Antidiabetic activity evaluation of Onobrychis species on alloxan-induced diabetic mice

In the current study, four Onobrychis species, O. albiflora Hub.-Mor., O. argyrea Boiss. subsp. argyrea Boiss., O. galegifolia Boiss., and O. tournefortii (Willd.) Desv. were collected from Anatolia to be evaluated for their antidiabetic activities. Methanol water extracts of the aerial parts were used for experiments. An alloxan-induced diabetic mice test model was used. Phytochemical analysis of the tested extracts was investigated using the HPLC method. The highest activity was observed with treatment of O. albiflora aerial part extract. Significant decrements were detected in the blood glucose levels as follows: 180.83±47.48 and 252.83±50.47mg/dL at 100 mg/kg and 200 mg/kg doses of O. albiflora, respectively, when compared to the isotonic saline solution control group, eliciting a blood glucose level of 494.20±27.32. Among the tested standard compounds, rutin and isoquercetin were detected in the examined species. The highest amount of rutin (1.1981±0.0017%) and isoquercetin (0.7318±0.0197%) were found in O. albiflora and O. argyrea subsp. argyrea, respectively. Antidiabetic activities of the tested Onobrychis species seem to indicate a possible correlation with their rutin and isoquercetin contents. Therefore, rutin and isoquercetin may be the antidiabetic compounds that contribute to the antidiabetic activity of the tested Onobrychis species.

Antifungal activity of some Sternbergia taxa: effects on germ tube and biofilm formation

Natural products are rapidly becoming the primary sources of novel antimicrobial agents, as resistance to existing antimicrobial agents is increasing. Apart from determining the antimicrobial activity of natural products, it is also important to understand their effects on the virulence factors of microorganisms. This study aimed to determine the antimicrobial activity of Sternbergia species prevalent in Turkey and investigate their role in the inhibition of germination tube and biofilm formation, both of which are known to be important virulence factors of Candida albicans. The antimicrobial activities of the plant extracts were evaluated using bore-plate and broth microdilution method. The extracts' capacity to inhibit the formation of the germ-tube was also evaluated. The findings of our study revealed that Sternbergia lutea, Sternbergia vernalis possessed antimicrobial activities, with MIC values ranging between 0.048 mg/mL and 0.39 mg/mL. The highest antimicrobial activity was observed against Candida dubliniensis (0.048 mg/mL). While evaluating the inhibition of fungal germination activities, S. vernalis extract (at a concentration of 0.09 mg/mL) was found to be the most effective against C. albicans ATCC 90028 strain. The results also indicated that S. vernalis extracts at sub-MIC levels inhibited germ tube formation and modulated the tail-length of germinated cells, both of which are important virulence factors of C. albicans. Furthermore, the inhibition of biofilm-formation was also investigated, and it was found that two Sternbergia spp. extracts at or below MIC levels inhibited biofilm formation.