RASOLOHERY

The determination of the chemical structure of an isolated vasodilatory molecule from Ludwigia octovalvis (Jacq.) P.H. Raven (Onagraceae) was undertaken. This molecule was isolated from n-butanolic extract using bioassay-guided isolation with preparative plate chromatographic techniques and its structure was determined using spectroscopy (UV, 1D- and 2D NMR, MS). The vasodilatory activity of the isolate was investigated on guinea pig isolated aorta. The results show 3 spots from n-butanolic extract with respective retention factor (Rf) of 0.14, 0.6 and 0.91. Pharmacological investigations showed that the isolated molecule with Rf 0.91 relaxes the isolated aorta pre-contracted by norepinephrine. Data from chemical shifts (δH) and spin-spin coupling constants (JHH) were compared with literature to confirm the isolate as rutin. This is the first report of rutin isolated from Ludwigia octovalvis.

Our objective was to study the activity of Ludwigia octovalvis hydro alcoholic extract in rats made experimentally hypertensive by a hypersodic diet. After 21 days of this diet, the systolic and diastolic blood pressure of these animals increases to 200.1 ± 1.5 / 155.6 ± 1.5 mm Hg, respectively. Administered orally, the extract reduces this high blood pressure. The control group blood pressure returned to its normal value (113.2 ± 1.2/76.3 ± 1) mm Hg after 24 days, versus 9th, 15th and 19th days for animals treated with the extract at doses of 400, 200 and 100 mg / kg (P <0.05). It does not have any diuretic activity but relaxes the isolated aorta contracted with norepinephrine 10-4 M with an EC50 equal to 1.18 ± 0.02 mg/ml. These results indicate that Ludwigia octovalvis extract has an antihypertensive activity by its vasodilator property. The polyphenols, triterpenoids and flavonoids in the extract may be responsible for its hypotensive activity.

Ludwigia octovalvis is used to treat stomachache in Malagasy traditional medicine. The present study was carried out to evaluate the anti-ulcer activity of its hydroalcoholic leaf extract in rats. Pylorus ligation and indomethacin-induced models were used to evaluate its anti-secretory and mucoprotective activities. Cimetidine (100 mg/kg) and Misoprostol (1.43 µg/kg) were used as the standard drugs. The extract was administered orally at doses 150, 300 and 600 mg/kg. The extract exhibited significant ulcer inhibition in indomethacin-induced ulcer model. The lesion surface area of the control group mucosa is equal to 6.2 ± 0.50 mm2, versus 4.32 ± 0.1, 2.75 ± 0.10 and 1.12 ± 0.05 mm2 in rat treated with the extract, and 2.1 ± 0.1 mm2 for the rats treated with misoprostol (p<0.05). It also reduces the gastric content acidity, which is equal to 2.79 ± 0.1 in control group, to 3.13 ± 0.1, 3.25 ± 0.2 and 5.31 ± 0.2 in the animals treated with the extract and 5.79± 0.1 for the animals treated with cimetidine (p<0.05). The extract showed significant reduction in mucosa lesion surface area and gastric content acidity, dose dependent compared to control.

Chemical and biological investigation of the Madagascar endemic plant Saldinia proboscidea led to the isolation of an isomer of artemisinin, (−)-6-epi-artemisinin (2). Its structure was elucidated using a combination of NMR and mass spectrometry. The absolute configuration was established by chemical syntheses of compound 2 as well as a new stereoisomer (3). The comparable bioactivities of artemisinin (1) and its isomer (−)-6-epi-artemisinin (2) revealed that this change in configuration was not critical to their biological properties. Bioactivity was assessed using an apoptosis induction assay, a SARS-CoV-2 inhibitor assay, and a haematin polymerization inhibitory activity (HPIA) assay. This is the first report of an artemisinin-related compound from a genus not belonging to Artemisia and it is the first isolation of an artemisinin-related natural product that is the opposite enantiomeric series relative to artemisinin from Artemisia annua.

Senecio gossypinus Bakeris an endemic species encountered in the northern, southern, western and central parts of Madagascar. Phytochemical screening of the EtOH extract from the leaves revealed the presence of flavonoids, sterols and polysaccharides. Fractionation of the hexane and EtOAc extracts led to the isolation of the mixture of a-amyrin (1) and b-amyrin (2), and kaempferol-3-O-α-L-arabinopyranoside (3), respectively. Compound 3 exhibited potent antimicrobial activity in vitro against Pseudomonas aeruginosa, Proteus mirabilis, Streptococcus agalactiea, Staphylococcus aureus, Candida albicans with inhibition zones of 13mm, 19mm, 15mm, 12mm and 9mm, respectively, at a test dose of 10 µg/disk using the disk diffusion method. Moreover, compound 3 showed moderate antioxidant activity against the free radical DDPH with an IC50 value of 1.90mg/mL. These results gave support to the traditional uses of the studied plant for the treatment of colic, bronchitis and wounds.

Objective: In the present study, the essential oil of Athroisma proteiformis was characterized for the first time. Method: GC-HRMS (Gas Chromatography-High Resolution Mass Spectrometry) was performed for qualitative and quantitative analysis of the phytochemicals present in the extract. Chemical analyses were conducted to evaluate the total phenols, total flavonoids and antioxidant activity of the extract. Results: Of the 130 peaks detected, 50 were studied and 30 compounds were clearly identified. The main components of the extract were p-cymen-8-ol, the major compound (13.37%), followed by caryophyllene oxide (12.02%), o-cymene (7.79%), humulene epoxide II (7.62%) and limonene (7.35%). The essential oil of Athroisma proteiformis exhibited a good antioxidant activity. The Athroisma extract IC50 values were lower than those of the antioxidant standards used in the FRAP and ABTS tests, ascorbic acid and BHT, and lower than glutathione in the OH radical reducing power test. On the contrary, in the DPPH test, IC50 was higher for A. proteiformis than for ascorbic acid or BHT. Conclusion: It can be concluded that the A. proteiformis plant can be used as a source of natural antioxidants but the consequences on human health should first be carefully studied due to the large number of compounds present in the oil. Keywords: Antioxidant activity, Asteraceae, Athroisma proteiformis, caryophyllene oxide, essential oil, p-Cymen-8-ol.

Seed isoflavone content is influenced by environment and genotype, but seed fractions such as hypocotyls and cotyledons display highly contrasted isoflavone contents and compositions. Moreover, the isoflavone content of hypocotyls appears less influenced by environment than that of cotyledons. The purpose of this study was to better understand isoflavone distribution between the two parts of the embryo during seed maturation. The accumulation kinetics of individual and total isoflavones in hypocotyls and cotyledons were recorded in three growth conditions (two years in greenhouse, and one year in the field) in four soybean [Glycine max (L.) Merr.] cultivars having contrasted isoflavone contents and compositions in their seed fractions, from 20 days after flowering (DAF, R5 stage) to seed maturity (R8 stage). As soon as 20 DAF, early isoflavone accumulation was observed in hypocotyls, whereas the isoflavone accumulation the in cotyledons began at R6 stage, after hypocotyl content had reached a plateau. Depending on the growth conditions, a continuous accumulation up to maturity was observed in cotyledons, resulting in a fourfold increase of the total isoflavone content. But whatever the growth conditions, isoflavone accumulation in hypocotyls was unchanged, suggesting that hypocotyl isoflavone content could mainly be under genotypic control. This study clearly shows that isoflavone synthesis and accumulation result from highly differenti ated pathways in hypocotyls and cotyledons.

AbstractBACKGROUND: Isoflavone content in soybean seeds is strongly influenced by both environment and genotype. However, little is known about the effect of environment and genotype on isoflavones in germ versus cotyledons. To determine the effect of temperature and soil moisture status during soybean seed development on seed isoflavone concentration and composition, a set of two French and three US cultivars of similar maturity were grown in the greenhouse. At the R6 growth stage, plants were subjected to one of three night/day temperature regimes (13/23°, 18/28° or 23/33 °C) in either optimal or sub‐optimal soil water conditions.RESULTS: In cotyledons, a three‐ to six‐fold variation in total isoflavone content was observed between the high and low temperature treatments, whereas the germ contents had less than a two‐fold variation. Soil water supply had less effect than temperature on the isoflavone contents and compositions. In both seed parts, the isoflavone concentrations were highly dependent on the cultivar.CONCLUSION: These results show that isoflavone content and composition in cotyledon and germ are unrelated and it should be possible to independently manipulate these seed traits through plant breeding and crop management systems. Copyright © 2007 Society of Chemical Industry