https://nova.newcastle.edu.au/vital/access/ /manager/Index en-au 5 https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:34580 Helicteres hirsuta Lour. (H. hirsuta L.) has been used as a traditional medicine for treatment of various ailments such as malaria and diabetes in Southeast Asian countries. This study aimed to optimize the conventional extraction conditions for obtaining the highest levels of phenolics, flavonoids, and antioxidant activities within H. hirsuta L. using response surface methodology. The Box–Behnken design was employed to evaluate the effects of extraction time, temperature, and the sample‐to‐solvent ratio on bioactive compound yield and antioxidant capacity of H. hirsuta L. The results indicated that the sample‐to‐solvent ratio had the strongest impact on bioactive compounds and antioxidant power of H. hirsuta L. and revealed the optimum extraction conditions to include temperature of 60 °C, time of 35 min at the sample‐to‐solvent ratio of 1 : 100 g/mL using 40% (v/v) methanol as the solvent. Under these conditions, the highest levels of total phenolic content and total flavonoid content were 16.87 mg GAE/g and 17.55 mg CE/g, respectively, significantly higher than the values obtained using water as the solvent. When preparing powered crude extract from H. hirsuta L., the ratio of 3 : 100 (g/mL) was suggested for the saving of 67% of solvent volume and energy required for solvent removal, as similar total phenolic content and total flavonoid content yield (86–87%) as well as antioxidant activities were obtained in comparison with the ratio of 1 : 100 (g/mL).]]> Wed 09 Feb 2022 15:55:50 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:33964 Helicteres hirsuta Lour. (H. hirsuta), which has been used as a traditional medicine for malaria and diabetes treatment. Results showed that either ultrasonic temperature or sample-to-solvent ratio had a greater influence on extraction efficiency of total phenolics, flavonoids and antioxidant capacity than that of methanol concentration. Optimal extraction conditions were determined to be ultrasonic temperature of 60 °C, ultrasonic time of 25 min, ultrasonic power of 150W, sample-to-solvent ratio of 3:100 g/mL, and a solvent composition of 40% (v/v) aqueous methanol. Under these conditions, 15.97 mg GAE/g of phenolics, 16.42 mg CE/g of flavonoids, and 13.34 g/100 g of extractable solids were obtained. The highest values for DPPH, ABTS and FRAP assays were also obtained under these conditions, with the exception of CUPRAC (88% maximum value). These optimal extraction conditions can be applied to prepare powdered crude extract for further isolation and purification of individual bioactive compounds for potential use in the pharmaceutical industry.]]> Wed 09 Feb 2022 15:54:39 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:34077 Helicteres hirsuta Lour. The results revealed that all the three powdered extracts from the leaves and the stems possessed high levels of phenolics (177.07–241.03 mg GAE g⁻¹), flavonoids (158.03–280.06 mg CE g⁻¹) and saponins (165.77–1035.33 mg ESE g⁻¹) and exhibited strong antioxidant capacity. HPLC analysis identified nine major compounds in the leaf powder crude extract; however, the leaf aqueous fraction had three extra compounds; whereas, the saponin-enriched butanol leaf fraction had seven extra compounds. For the stems, twelve main compounds were evident in either the powdered crude extract or the aqueous fraction, and five new compounds were revealed in the saponin-enriched butanol fraction. The findings revealed that the powdered aqueous fractions and saponin-enriched butanol fractions are potential sources of biologically active compounds for further investigation and industrial utilisation.]]> Wed 06 Feb 2019 14:24:17 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:36561 Mon 13 Sep 2021 16:06:41 AEST ]]>