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.

Cochlospermum regium (Mart. ex Schrank) Pilg.: Evaluation of chemical profile, gastroprotective activity and mechanism of action of hydroethanolic extract of its xylopodium in acute and chronic experimental models.

ETHNOPHARMACOLOGICAL RELEVANCE: Cochlospermum regium (Bixaceae) is a native shrub of Brazil and its xylopodium (infusion/decoction) is being used for the treatment of gastritis, ulcers, arthritis, intestinal infections, gynaecological infections, skin diseases, among others. The aim of the present study was to evaluate the gastroprotective/antiulcer activity and the mechanism of action of hydroethanolic extract of C. regium xylopodium (HECr), using in vitro and in vivo models. Additionally, phytochemical constituents were identified by high-performance liquid chromatography (HPLC). MATERIALS AND METHODS: C. regium xylopodium was macerated with ethanol/water to obtain the HECr. The phytochemical characterisation was carried out by HPLC. The antiulcer efficacy of HECr (25, 100 and 400 mg/kg, p.o.) was evaluated using acute acidified ethanol (HCl/EtOH), piroxicam and water immersion-induced experimental ulcer models. Chronic gastric ulcer healing activity of HECr was evaluated through acetic acid (99.8%) - induced model. Histological analysis and myeloperoxidase (MPO), glutathione (GSH), catalase (CAT) activities were also evaluated in chronic ulcer induced gastric tissues. The plausible mode of action of the HECr was assessed by estimation of gastric wall mucus production and the role of gastric secretion in pylorus ligature. The animals were also pre-treated with various inhibitors which includes indomethacin (10 mg/kg, p.o.) a selective inhibitor of cyclooxygenase, L-NAME (10 mg/kg, i.p.), an inhibitor of nitric oxide synthase, glibenclamide, a ATP-sensitive potassium channels (K+ATP) blocker (5 mg/kg, p.o.) or yohimbine (2 mg/kg, i.p.), an α2-adrenergic receptor antagonist. In vitro, Helicobacter pylori action was done by broth microdilution method. RESULTS: The HPLC analysis data revealed the presence of gallic acid, rutin, myricetin, morin and kaempferol. HECr promoted protective effect against acute ulcers induced by HCl/EtOH with inhibitions of 47.52% (p < 0.01) and 62.69% (p < 0.001) at 100 and 400 mg/kg, and in piroxicam by 34.11% (p < 0.05), 49.14% (p < 0.01) and 61.34% (p < 0.001), at 25, 100 or 400 mg/kg, respectively, and in water restraint stress by 78.26% inhibition, p < 0.001, at the dose of 400 mg/kg when compared to the vehicle control group respectively. In the chronic gastric ulcer model, HECr (25, 100 and 400 mg/kg p.o.) significantly (p < 0.001) decreased the injured area by 58.80%, 77.87% and 71.10% respectively. Histological examination indicated that oral treatment of HECr promoted healing of gastric lesions by regenerating gastric mucosa layer with less inflammatory cells. HECr augmented the GSH, CAT activities and reduced MPO level. The pre-treatment with HECr increased the gastric wall mucus production. It also significantly altered the gastric secretion parameters by causing the reduction in the gastric juice volume, elevated the pH level and reduced the total acidity at all doses tested when compared with the vehicle group. HECr at the most active dose (100 mg/kg) reversed completely the reduction of PGs, NO production, closure of K+ATP- channels and α2-adrenoreceptor blockage - induced damages. In microdilution assay, the HECr showed good anti-Helicobacter pylori effect with MIC = 100 µg/mL. CONCLUSION: The HECr presented preventive and curative effects in the experimental gastric ulcer models, besides good anti-Helicobacter pylori activity, which supports the traditional medicinal use of the xylopodium of this plant for gastrointestinal diseases. The underlying mechanisms of this antiulcerogenic/antiulcer action involve, at least, augmentation of mucus production, inhibition of gastric secretion, stimulation of PGs and NO synthesis. And that it involves activation of K+ATP channels and α-2-adrenergic receptors, in addition to an antioxidant activity, probably due to the presence of gallic acid and flavonoids in HECr.