Antioxidant activity enhancement and oxidative damage inhibition by Lagenaria breviflora fruit and Xanthosoma sagittifolium corm in hypertensive Wistar rats.

Cardiovascular diseases are the leading causes of mortality in the world today with hypertension being the major clinical presentation of these diseases. This study assessed the anti-hypertensive effects of Lagenaria breviflora whole fruit and Xanthsoma  sagittifolium corms in experimentally inudced hypertensive Wistar rats. The ability of the plants to ameliorate oxidative damage accompanying hypertension was evaluated using changes in oxidative stress markers as well as monitoring of cardiovascular parameters. Hypertension was induced by intraperitoneal injection of DOCA salt twice weekly and daily inclusion of NaCl (1%) in drinking water. Methanol extracts of L.breviflora or X. sagittifolium was administered to hypertensive rats for 35 days and the outcome was compared to hypertensive rats administred with lisinopril or hydrochlorothiazide and a group of normotensive rats (control). Systolic, diastolic and mean arterial pressures were determined on day 34 and blood sample collected on day 35. The rats were thereafter humanely sacrificed, and organs were harvested. This study showed that the extracts lowered blood pressure, free protein thiols but increased toal protein, gluthathione peroxidase, reduced glutathione, glutathione S-transferase, catalase and nitric oxide in the heart, kidney and liver compared to untreated hypertensive rats. However, malondialdehyde levels and hydrogen peroxide activities were reduced. L. breviflora fruit and X. sagittifloium corm exhibited antihypertensive properties and ameliorate oxidative damage associated with hypertension by enhancing the antioxidant defense sysyem and inhibiting generation of free radicals.

An efficient in vitro propagation protocol of cocoyam [Xanthosoma sagittifolium (L) Schott].

Sprouted corm sections of "South Dade" white cocoyam were potted and maintained in a greenhouse for 8 weeks. Shoot tips of 3-5 mm comprising the apical meristem with 4-6 leaf primordial, and approximately 0.5 mm of corm tissue at the base. These explants were treated to be used into the culture medium. A modified Gamborg's B5 mineral salts supplemented with 0.05 µM 1-naphthaleneacetic acid (NAA) were used throughout the study. Thidiazuron (TDZ) solution containing 0.01% dimethyl sulfoxide (DMSO) was used. Erlenmeyer flasks and test tubes were used for growing cultures. The effect of different media substrate, thidiazuron, and the interaction between TDZ and Benzylaminopurine (BAP) on cocoyam culture were tested. Results indicated that cocoyam can be successfully micropropagated in vitro through various procedures. All concentrations tested (5-20 µM BAP and 1-4 µM TDZ) produced more axillary shoots per shoot tip than the control without cytokinins. Greater proliferation rates were obtained through the use of 20 µM BAP and 2 µM TDZ, respectively, 12 weeks from initiation. Shoots produced with BAP were larger and more normal in appearance than those produced with TDZ, which were small, compressed, and stunted. The use of stationary liquid media is recommended for economic reasons.

The glycemic index (GI) and glycemic load (GL) of five commonly consumed foods of the South Pacific.

Glycemic index (GI) has been widely used in the management of blood sugar levels among diabetes however; in the South Pacific very little information regarding the GI of local foods is made available. The objectives of this research were to determine the glycemic index and the glycemic load of 5 South Pacific foods, which have not been studied. The foods tested were plantain (Musa AAB), tannia (Xanthosoma sagittifolium), roti or chappati, homemade pancake and Lees cabin crackers. Glucose powder mixed in 200 mL of water was used as reference food. Eight apparently healthy indigenous Fijian males from the Fiji Military Forces aged 25-36 years old were recruited for this study. Participants were given a 50 g carbohydrate portion of the test foods to ingest after a 10-12 hour fast the night before the test and the standard reference food were administered to participants on different days for comparison. In the morning, capillary blood samples were drawn from the fingers at 0 min, 15, 30, 45, 60, 90 and 120 minutes postprandially and the blood glucose level was determined. The equation of Wolever using computer software was used to calculate the glycemic index and the glycemic load was calculated using the formular provided in the Harvard Health Online. The results showed that individuals respond to foods differently thus affecting the GI average values. The glycemic index has been categorized by Miller as low GI is pounds 55, moderate GI is between 56-69 and high GI is > or = 70. All the five carbohydrate foods understudy have moderate GI values ranging from 59 to 68. The Glycemic Load (GL) for cabin biscuit was the highest.