https://ogma.newcastle.edu.au/vital/access/ /manager/Index en-au 5 https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:36608 Tue 16 Jun 2020 10:51:27 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:42901 Helicteres hirsuta Lour. (H. hirsuta L.) have been used as traditional medicines, however limited studies have been conducted on the preparation of dried material or the extraction of bioactive compounds. This study aimed to determine the effect of various solvents and drying methods on the bioactive compound yield and antioxidant capacity of the H. hirsuta L. stem. The results showed that water was the best solvent for obtaining the highest levels of phenolics and flavonoids, whereas methanol was the solvent of choice for saponin extraction. Among assessed drying methods, hot-air drying at 80C revealed as the best method to maintain the bioactive components (phenolics of 8.99 mg GAE/g, flavonoids of 9.60 mg CE/g and saponins of 15.18 mg ESE/g), and DPPH, ABTS, and FRAP antioxidant activities. Thus hot-air drying at 80C is recommended for preparation of dried H. hirsuta L. stem for further processing steps.]]> Tue 06 Sep 2022 15:35:23 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:34478 Catharanthus roseus (L.) G. Don (C. roseus) is well known as an important medicinal plant, with compounds such as the vinca alkaloids isolated for their anticancer activity. As such, it is important to determine the effective solvent for bioactive compound extraction from this plant and the suitable drying methods for preparation of starting material. The aims of this study were to determine the effect of extraction solvents and drying methods on bioactive compounds and antioxidant properties of C. roseus. Water was found to be the optimal solvent for phenolic and flavonoid extraction; whereas, methanol was the best solvent for saponin and proanthocyanidin extraction. The data also revealed that vacuum drying at 50°C was suitable for drying the leaf and the flower which contained high levels of phenolics and flavonoids, while infrared drying at 35°C was recommended for drying the stem and the root which had high saponin content. Practical applications: This study suggested that different parts of C. roseus had different suitable thermal drying methods. For the leaf and the flower, vacuum drying at 50°C was the optimal drying method, whereas infrared drying at 35°C was suitable for drying the stem and the root. These drying conditions can be easily applied for preparation of dried plant parts with high levels of bioactive compounds in the large scale. Importantly, the data indicated that the stem and the root of C. roseus which were considered as waste when the leaf was used for exploiting alkaloids, possessed great content of saponins. Therefore, these parts can be further used for isolation and purification of saponins.]]> Fri 03 Dec 2021 10:35:25 AEDT ]]>