Antioxidant and toxicity studies of 50% methanolic extract of Orthosiphon stamineus benth.

The present study evaluated the antioxidant activity and potential toxicity of 50% methanolic extract of Orthosiphon stamineus (Lamiaceae) leaves (MEOS) after acute and subchronic administration in rats. Superoxide radical scavenging, hydroxyl radical scavenging, and ferrous ion chelating methods were used to evaluate the antioxidant properties of the extract. In acute toxicity study, single dose of MEOS, 5000 mg/kg, was administered to rats by oral gavage, and the treated rats were monitored for 14 days. While in the subchronic toxicity study, MEOS was administered orally, at doses of 1250, 2500, and 5000 mg/kg/day for 28 days. From the results, MEOS showed good superoxide radical scavenging, hydroxyl radical scavenging, ferrous ion chelating, and antilipid peroxidation activities. There was no mortality detected or any signs of toxicity in acute and subchronic toxicity studies. Furthermore, there was no significant difference in bodyweight, relative organ weight, and haematological and biochemical parameters between both male and female treated rats in any doses tested. No abnormality of internal organs was observed between treatment and control groups. The oral lethal dose determined was more than 5000 mg/kg and the no-observed-adverse-effect level (NOAEL) of MEOS for both male and female rats is considered to be 5000 mg/kg per day

Antioxidant and Toxicity Studies of 50% Methanolic Extract of Orthosiphon stamineus Benth

The present study evaluated the antioxidant activity and potential toxicity of 50% methanolic extract of Orthosiphon stamineus (Lamiaceae) leaves (MEOS) after acute and subchronic administration in rats. Superoxide radical scavenging, hydroxyl radical scavenging, and ferrous ion chelating methods were used to evaluate the antioxidant properties of the extract. In acute toxicity study, single dose of MEOS, 5000mg/kg, was administered to rats by oral gavage, and the treated rats were monitored for 14 days. While in the subchronic toxicity study, MEOS was administered orally, at doses of 1250, 2500, and 5000mg/kg/day for 28 days. From the results, MEOS showed good superoxide radical scavenging, hydroxyl radical scavenging, ferrous ion chelating, and antilipid peroxidation activities. There was no mortality detected or any signs of toxicity in acute and subchronic toxicity studies. Furthermore, there was no significant difference in bodyweight, relative organ weight, and haematological and biochemical parameters between bothmale and female treated rats in any doses tested.No abnormality of internal organs was observed between treatment and control groups.Theoral lethal dose determined wasmore than 5000mg/kg and the no-observed-adverse-effect level (NOAEL) of MEOS for both male and female rats is considered to be 5000mg/kg per day

All-Electrical Skyrmionic Bits in a Chiral Magnetic Tunnel Junction

Topological spin textures such as magnetic skyrmions hold considerable promise as robust, nanometre-scale, mobile bits for sustainable computing. A longstanding roadblock to unleashing their potential is the absence of a device enabling deterministic electrical readout of individual spin textures. Here we present the wafer-scale realization of a nanoscale chiral magnetic tunnel junction (MTJ) hosting a single, ambient skyrmion. Using a suite of electrical and multi-modal imaging techniques, we show that the MTJ nucleates skyrmions of fixed polarity, whose large readout signal - 20-70% relative to uniform states - corresponds directly to skyrmion size. Further, the MTJ exploits complementary mechanisms to stabilize distinctly sized skyrmions at zero field, thereby realizing three nonvolatile electrical states. Crucially, it can write and delete skyrmions using current densities 1,000 times lower than state-of-the-art. These results provide a platform to incorporate readout and manipulation of skyrmionic bits across myriad device architectures, and a springboard to harness chiral spin textures for multi-bit memory and unconventional computing.Comment: 8 pages, 5 figure

Solid-liquid extraction of betel leaves (Piper betle L.)

This work investigated the effects of extraction temperature on the quality of extract and the kinetics of solid-liquid extraction of betel leaves. In this study, the effects of extraction temperature on the quality of extract were evaluated by comparing the concentration of its active compounds, including hydroxychavicol (HC) and eugenol (EU). The results indicate that the increase of extraction temperature led to the increase of the concentration of HC. EU concentration was decreased when temperatures higher than 60C were used. The kinetics data show that the extraction process reached equilibrium in a short time – about 40 min. Two models, namely equilibrium-dependent solid-liquid extraction (EDSLE) model and diffusion-dependent solid-liquid extraction model were applied to describe the extraction process. By comparing the values of correlation coefficients, the EDSLE model was found to be more suitable in describing the extraction process as it provided a better fit to the experimental data

Drying of betel leaves (Piper betle L.): quality and drying kinetics

This work studied the effects of drying temperature on the quality and drying kinetics of betel leaves (Piper betle L.). As the drying process applies heat on the product, this might lead to the degradation and decomposition of valuable phytochemicals within the herbs. In this study, the effect of drying temperature on the quality of dried leaves was studied by analyzing the change of major phytochemicals found in the leaves, which are hydroxychavicol and eugenol. The results indicate that the content of major compounds increased with temperature from 40 to 70°C but underwent decomposition when the leaves dried at 80°C. Besides that, the drying kinetics for different drying temperatures also studied. The kinetics results show that the increase of drying temperature shortened the total drying time. Five thin-layer models were selected in describing the drying process of betel leaves. The logarithmic model was found to be the most suitable one

Modelling of freezing kinetics of extract of betel leaves (Piper betle L.)

Betel is a native medicinal plant from central and eastern parts of Peninsular Malaysia. It is now an important commercial crop in India and Sri Lanka. There are various beneficial bioactivities discovered in this herb including anti-carcinogenic, anti-inflammatory, antioxidant, and antimicrobial properties. Freeze drying is one of the common methods used to dehydrate the herbal aqueous extract. This work studied the freezing process of aqueous extract of betel leaves (Piper betle L.). The effects of different freezing temperatures on the freezing kinetics were investigated. Freezing temperatures of -20, -25, -30°C were selected for the study. The freezing time which was taken as the time required for the temperature of the sample to reach the freezing temperature was determined from the kinetics data. The freezing point of betel leaves extract was determined as -4°C. The freezing process was described with numerical model. The predicted data showed good agreement with the experimental results

Antioxidant and Toxicity Studies of 50% Methanolic Extract of Orthosiphon stamineus Benth

The present study evaluated the antioxidant activity and potential toxicity of 50% methanolic extract of Orthosiphon stamineus (Lamiaceae) leaves (MEOS) after acute and subchronic administration in rats. Superoxide radical scavenging, hydroxyl radical scavenging, and ferrous ion chelating methods were used to evaluate the antioxidant properties of the extract. In acute toxicity study, single dose of MEOS, 5000 mg/kg, was administered to rats by oral gavage, and the treated rats were monitored for 14 days. While in the subchronic toxicity study, MEOS was administered orally, at doses of 1250, 2500, and 5000 mg/kg/day for 28 days. From the results, MEOS showed good superoxide radical scavenging, hydroxyl radical scavenging, ferrous ion chelating, and antilipid peroxidation activities. There was no mortality detected or any signs of toxicity in acute and subchronic toxicity studies. Furthermore, there was no significant difference in bodyweight, relative organ weight, and haematological and biochemical parameters between both male and female treated rats in any doses tested. No abnormality of internal organs was observed between treatment and control groups. The oral lethal dose determined was more than 5000 mg/kg and the no-observed-adverse-effect level (NOAEL) of MEOS for both male and female rats is considered to be 5000 mg/kg per day

Endothelium-dependent vasorelaxation and antiproliferation activities of chloroform extract F5 fraction from Crinum amabile Donn ex Ker Gawl. leaves

Medicinal plants are potential sources of bioactive compounds, which due to their multiple pharmacological benefits, could be developed into promising therapeutic drugs. Crinum amabile possesses various biological activities such as antimalaria, anticancer and antihypertension. These encouraging findings had led to the selection of this plant species as a viable candidate for developments of anticancer and antihypertension products. Therefore, this research was undertaken to investigate the anticancer (cytotoxicity, apoptosis and anti-angiogenesis) and the antihypertensive properties of this plant. The possible pathways to the underlying mechanism of respective activities were also elucidated. Firstly, the leaves of C. amabile were serially extracted using Soxhlet’s apparatus to yield four different extracts: petroleum ether extract (PE), chloroform extract (CE), methanol extract (ME) and water extract (WE). Preliminary assays (both anticancer and vasorelaxation) showed that CE exhibited the highest pharmacological effects. Thus, CE was fractionated using column chromatography and standardized through thin layer chromatography to produce six individual fractions. Next, the cytotoxicity of all these extracts and fractions were tested on various human cancer cell lines using MTS cytotoxicity assay. Results indicated that F5 fraction exhibited non-cell-specific cytostatic effects on most of the cancer cell lines, with MCF-7 breast cancer cells being the most susceptible. However, further studies using two apoptosis assays: annexin-V and DNA fragmentation assay showed that F5 fraction did not induce cell apoptosis on MCF-7 cells and no DNA fragmentations were detected. Nonetheless, cell proliferation assay using MTT assay revealed that F5 fraction was able to inhibit normal cell proliferation as well as VEGF-induced cell proliferation of normal endothelial cell: HUVECs. Data from this study illustrated that F5 fraction from leaf CE of C. amabile was able to exhibit cytostatic effect through anti-proliferation and anti-angiogenesis activities rather than induction of cell apoptosis. Meanwhile the vasorelaxation activities of C. amabile extracts and fractions were elucidated on both phenylephrine pre-contracted intact and denuded rat aortic rings. The results indicated that F5 fraction exhibited the highest vasorelaxation activities and produced both endothelium-dependent and endothelium-independent vasorelaxation. In depth studies of its mechanism pathway(s) elucidated that the endotheliumdependent vasorelaxation induced by F5 fraction was primarily achieved through the stimulation of PGI2 production and partial association with NO/sGC/cGMP activation pathway. The study proposed that C. amabile can serve as a promising lead candidate for both discovery and development of new cytotoxic or vasodilator drugs