Phenolic compounds of Eugenia involucrata (Myrtaceae) extracts and associated antioxidant and inhibitory effects on acetylcholinesterase and α-glucosidase.

Eugenia involucrata DC. (Myrtaceae), popularly known as "cereja-do-Rio-Grande", is a native tree from Brazil, popularly used as a hypoglycemiant. Crude hydroalcoholic extract (CHE) and fractions (insoluble (FI), dichloromethane (FDM), ethyl acetate (FEA) and butanol (FBu)) of leaves were assessed to determine the phenolic chemical composition by HPLC-ESI-MS/MS. 10 compounds were identified, being 7 new for this species: rutin, isoquercitrin, luteolin-7-O-rutinoside, mandelic acid, naringenin, luteolin-7-O-glucoside and salicylic acid. Extract and fractions showed inhibitory activity on acetylcholinesterase (AchE) enzyme (best result: IC50 = 44.19 µg mL-1, for FEA) and α-glucosidase (α-Glu) (best result: IC50 = 31.25 ± 0.15 µg mL-1, for CHE). The observed antioxidant and inhibitory activity on the AchE and α-Glu is due to, at least in part, the presence of phenolic compounds in the samples.

Phenolic profile by HPLC-ESI-MS/MS of six Brazilian Eugenia species and their potential as cholinesterase inhibitors.

Eugenia genus is known for its phenolic metabolites, which may influence the progression of the Alzheimer Disease. This study aimed to evaluate the anticholinesterase effects of six Eugenia species from Brazil. Leaves and stems were submitted to maceration (methanol) and partitioned with dichloromethane and ethyl acetate (EtOAc). Samples were screened (200 µg mL-1) for the inhibition of acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE). HPLC-ESI-MS/MS analysis allowed the identification of twenty-eight phenolic compounds. Regarding the enzymatic activity, EtOAc fraction of E. mattosii exhibited the best results. Chemical and pharmacological aspects of seasonal E. mattosii extracts were evaluated. The extract from leaves collected in the winter was the most effective for AChE, and the extract from leaves collected in the spring was the most effective for BuChE. Correlating the enzymatic results with the chemical data, it was possible to associate these effects to isoquercitrin, quercetin, catechin, epicatechin, procatecuic acid and myricitrin content.

Antiparasitic activity of two Brazilian plants: Eugenia mattosii and Marlierea eugeniopsoides.

Parasitoses are very common throughout the world, generating serious consequences for public health. Leishmaniosis and giardiasis are examples of fairly recurrent, but neglected diseases. Several higher plants have demonstrated promising activity against the parasites. The aim of this study was to evaluate the biological activity of extracts, fractions and isolated compounds from the leaves and stems of two Brazilian plants: Eugenia mattosii and Marlierea eugeniopsoides (Myrtaceae) against Leishmania and Giardia. XTT and the fluorimetric method were used to for this evaluation, respectively. Cytotoxicity was evaluated against HeLa cells. The results demonstrated that chloroform fractions of E. matosii and pinostrobin presented the most pronounced antiparasitic activity, with the CLF-stems being the most effective against Leishmania amazonensis and Leishmania braziliensis. Pinostrobin also presented activity against G. lamblia. Therefore, E. mattosii stems and pinostrobin may be considered possible targets for the continuity of studies against other parasites.

Phenolic profile by HPLC-ESI-MS/MS and enzymatic inhibitory effect of Bryophyllum delagoense.

Bryophyllum delagoense (Eckl. & Zeyh.) Druce, native to Madagascar, is popularly known as "abyssian cactus" and popularly used in folk medicine as an analgesic and healing agent. The study methodology was divided into the phytochemical study: fractionation and identification of phenolic compounds by HLPC-ESI-MS/MS from the methanolic extract (ME), and fractions (DCMF and EAF) of leaves of B. delagoense, and biological activity with acetylcholinesterase and α-glucosidase inhibition of extracts and fractions by in vitro enzymatic techniques. Twenty-seven phenolic compounds were identified, being the highest concentration of syringic acid (87.848 mg g-1). The DCMF fraction showed the best biological activity for inhibition of α-glucosidase enzyme (0.125 mg mL-1).

Sorocea guilleminiana Gaudich.: Wound healing activity, action mechanisms, and chemical characterization of the leaf infusion.

ETHNOPHARMACOLOGICAL RELEVANCE: Sorocea guilleminina Gaudich. is a tree or shrub endemic to Brazil. Its leaves are used in Brazilian folk medicine for the healing of wounds, stomach problems, inflammation and as diuretic. The present study evaluates the activity and action mechanisms of the healing properties of the aqueous extract of S. guilleminiana leaves (AESg), in experimental models in vivo and in vitro, as well as performs a phytochemical analysis of the extract. MATERIALS AND METHODS: The AESg was prepared by infusion: Ten g of dry leaves powder in 1 L hot water, soaked for 15 min, filtered, lyophilized, and stored at -30 °C. Phytochemical analyses were realized by colorimetry and HPLC/ESI/MS. Its' in vitro cytotoxicity was evaluated on fibroblastic N3T3 cells. The potential of the wound healing activity in vivo was evaluated using excision and incision wound rat models, by histopathology of the injured skin along with the determination of nitric oxide, cytokines (IL-1ß, IL-10, and TNF-α), and antioxidant parameters (GSH, MPO and CAT). In vitro wound healing activity was also demonstrated in scratched N3T3 cells, by measuring the proliferation/migration rate. RESULTS: The phytochemical analysis of the AESg revealed a strong presence of polar compounds, especially flavonoids (4 majoritarian), as well as terpenes and/or sterols (2 majoritarian). The AESg showed no toxicity in the N3T3 cell line (IC50 > 800 µg/mL). Topical treatment with the AESg showed an increase (p < 0.05) in wound contraction with 2 mg/g cream on days 5 and 9 (43.56% and 6.70% increase, respectively), and with 50 mg/g on days 7 and 9 (10.88% and 7.91%, respectively), compared to the vehicle (non-ionic neutral cream). Topical application of AESg (2 or 50 mg/g non-ionic cream) in incised wounds caused an increase in the force necessary for the rupture of the wound when compared to the vehicle group. No changes in cytokines (IL-1ß, IL-10, or TNF-α) or NO accumulation was found with up to 50 mg/g AESg treatment. For antioxidant activity on the incision wound, an increase in GSH levels was denoted with the AESg use, at the lowest and highest dose (2 and 50 mg/g) by 75.86% and 61.20% respectively, when compared to the vehicle. Also, the CAT activity was accentuated by AESg at the highest dose (50 mg/g) by 85.87%. Finally, the AESg at all doses attenuated MPO activity significantly in the incision wound by 71.35%, 73.21%, 78.08%, respectively. In the scratch test on N3T3 cells, the treatment with AESg resulted also in an increase in fibroblast proliferation/migration rate, compared to the vehicle. CONCLUSION: AESg is not cytotoxic. The results confirm the popular use of the leaf infusion of S. guilleminiana for the treatment of cutaneous wounds, possibly by stimulating the proliferation of fibroblasts with a consequent deposition of collagen, fastening rearrangement of collagen fibers, and greater transformation into myofibroblasts, essential in the healing process. Preliminary chemical analyzes of AESg revealed the presence mainly of phenolic compounds, being salicylic acid, gallic acid, pinocembrin and isoquercitrin the majoritarian ones.

Bauhinia forficata link, a Brazilian medicinal plant traditionally used to treat cardiovascular disorders, exerts endothelium-dependent and independent vasorelaxation in thoracic aorta of normotensive and hypertensive rats.

ETHNOPHARMACOLOGICAL RELEVANCE: Bauhinia forficata Link, commonly known as "cow's paw", is a native plant from South America. Its leaves are widely used in Brazilian folk medicine to treat diabetes and cardiovascular disorders. Although this species' biological potential has been extensively proven as an antidiabetic, anti-inflammatory and antioxidant agent, there is a lack of studies to evidence its action on the cardiovascular system. AIM OF THE STUDY: This study was designed to investigate the vascular effects of B. forficata leaves preparations and its majority compound kaempferitrin, as well as its aglycone form kaempferol, in rat aortic rings of normotensive (NTR) and hypertensive (SHR) rats. MATERIALS AND METHODS: Aorta rings from NTR and SHR precontracted with phenylephrine were exposed to cumulative concentrations of B. forficata extract, fractions (1-50 µg/mL) and compounds (0.001-0.3 µg/mL). The mechanisms involved in the vasorelaxant effect of ethyl-acetate plus butanol fraction (EAButF) were also evaluated. RESULTS: Although kaempferitrin is the most abundant compound found in both methanolic extract and EAButF, 24 minor phenolic compounds were identified in B. forficata leaves, including kaempferol. EAButF was the only with endothelium-dependent and independent vasorelaxant properties in both NTR and SHR. The incubation with L-NAME or ODQ completely blocked EAButF-induced vasorelaxation. On the other hand, the incubation with propranolol, atropine, indomethacin, glibenclamide or barium chloride did not change the vasorelaxant activity of EAButF (50 µg/mL). Nevertheless, the incubation with tetraethylammonium and 4-aminopyridine significantly influenced the EAButF activity. It was also shown that Ca2+ influx or efflux is not related to EAButF vasorelaxation potential. Kaempferitrin and kaempferol were also able to relax the rat aortic rings in 34.70% and 40.54%, respectively. CONCLUSIONS: This study shows, for the first time, the vasorelaxant effect of EAButF from B. forficata leaves, an effect that may be attributed to the modulation of vascular tone through nitric oxide/soluble guanylate cyclase pathway, and potassium channels. The bioactive kaempferitrin and kaempferol seem to be important for the effects observed with the fraction. Finally, preparations obtained from the leaves of B. forficata may be interesting candidates for new or complementary strategies regarding cardiovascular diseases.