Optimization of corrosion inhibition of essential oils of Alpinia galanga on mild steel using Response Surface Methodology

The use of plant extracts as corrosion inhibitors has gained prominence as replacement for synthetic organic compounds. The plant natural products have been found to be effective, cheap and eco-friendly anticorrosion agents. Corrosion inhibitions of essential oils of Alpinia galanga were investigated on mild steel in hydrochloric acid solution using weight loss method. The interactive effects of inhibitor concentration, temperature and time were optimized for maximum response of inhibition efficiency using Response Surface Methodology with Central Composite Design. The optimum inhibition efficiency of 88.5% at 775 ppm of inhibitor concentration, temperature of 320.4 K and reaction time of 3.75 hours was accomplished. The effectiveness of the inhibitor was also supported using scanning electron microscopy. The mechanism of interaction of both the inhibitor on mild steel surface was found to conform to the Langmuir adsorption isotherm

The ethnomedicinal, phytochemical and pharmacological properties of Phaleria macrocarpa (Scheff). Boerl

Phaleria macrocarpa (Scheff.) Boerl. is a dense evergreen tree of the family Thymelaeceae. This plant is popular with the name of Mahkota dewa, which is literally translated as God's Crown. All parts of this plant including fruits, seeds, stem, and leaves have well known therapeutic properties and have been extensively used in traditional medicine for the treatment of various diseases such as cancer, diabetes mellitus, allergies, kidney disorders, blood diseases, stroke, and acne with satisfactory results. Scientific findings on bioactivities of P. macrocarpa also demonstrated different pharmacological properties of various parts of this plant including cytotoxic, antidiabetic, antioxidant, anti-inflammatory, antibacterial, and antihypertensive activities. Phytochemicals studies of P. macrocarpa revealed the presence of several classes of compounds such as benzophenones, terpenoids, xanthones, lignans, acids, and sugars. This review aims to provide a critical overview on botanical description, traditional usage, phytochemicals, and pharmacological activities of P. macrocarpa

Globrauneine A–F: six new triterpenoid esters from the leaves of Globimetula braunii

Phytochemical study was conducted on the leaves of Globimetula braunii which is a hemi parasitic plant belonging to the family Loranthaceae. Extraction was carried out using cold extraction method with increasing polarity of solvents i.e n-hexane, CH2Cl2 and MeOH. The components were separated by chromatographic technique and the structures of the compounds were elucidated by extensive spectroscopic analyses including MS, FTIR, 1D and 2D NMR, HRMS and chemical methods. Six new pentacyclic triterpenoid esters named as globrauneine A (1), globrauneine B (2), globrauneine C (3), globrauneine D (4), globrauneine E (5), and globrauneine F (6), together with six known compounds (7 – 12) were successfully isolated from the leaves of G. braunii growing on Piliostigma thonningii. These results depict a substantial support to the chemotaxonomy of the genus Globimetula

Antioxidant property, traditional uses and chemical composition of seed oil plants of North-east India: A mini- review

Apart from being used as food, seed oils have also been used traditionally as medicinal products by several communities. However, the full medicinal potential of many seed oil plants is yet to be properly reviewed, particularly for their antimicrobial and antioxidant properties. North-East India has rich resources of seed oil plants. The availability of detailed information on these plants is quite limited. This review aims to explore and evaluate these seed oil plants of the North-East India with particular emphasis on their antimicrobial and antioxidant activities as well as chemical compositions. A comprehensive literature search on seed oil plants of this region has been performed. Seed oil yielding plants of this region can be categorized into two categories: plants that are used traditionally as sources of edible or medicinal oils and plants that are used for purposes other than as sources of oils. Many seed oil plants of this region have been reported to possess antimicrobial and antioxidant properties, and to produce various types of compounds. This review also highlights the importance of these plants in contributing to the local as well as the national economy of India

Bioassay-guided isolation of antioxidants and ?-Glucosidase inhibitors from the root of cassia sieberiana D.C. (fabaceae)

Bioassay-guided isolation was used to investigate the antioxidants and α-glucosidase inhibitors from extract of root of Cassia sieberiana. The ethyl acetate fraction demonstrated strong free radical scavenging (DPPH and ABTS+) and potent α-glucosidase inhibition. The subsequent fractionation and purification of the ethyl acetate fraction using silica gel chromatography and Sephadex LH-20, yielded; islandicin (1), chrysophanol (2), physcion (3), emodin (4), quercetin (5), kaempferol (6), dihydrokaempferol (7), and piceatannol (8). Quercetin (5) showed the most active antioxidant activity with IC50 values of 1.58 mM and 1.30 mM against DPPH and ABTS+ radicals, followed by piceatannol (8) with IC50 values of 3.96 mM and 3.28 mM, which is better than the standard BHT (with IC50 value 8.93 mM) and trolox (with IC50 value 8.25 mM), for DPPH and ABTS+ radicals scavenging activities, respectively. For the α-glucosidase inhibitory assay, quercetin (5) and piceatannol (8) showed higher potency against α-glucosidase with IC50 values of 5.73 μM and 7.37 μM respectively, than standard quercetin with IC50 value of 9.20 μM and acarbose with IC50 value of 14.12 μM. This study presents the first report on the α-glucosidase inhibitors from root of C. sieberiana and all the compounds are isolated from this source for the first time

Parametric analysis on a simple design water reaction turbine for low-head low-flow Pico-hydro generation system

This paper presents a parametric analysis of the outward flow reaction type turbine known as a Z-Blade turbine for low-head low-flow conditions. By applying the principles of mass conservation, momentum and energy, a nomogram was designed to investigate the theoretical performance characteristics. Based on the parametric analysis and the governing equations and experimental results, attempts have been made to prove that the mass flow rate, angular speed, centrifugal head, power output and efficiency respond dynamically to the water head, radius of the rotor, size of the PVC pipes and the nozzle exit area. A turbine with a 1” pipe diameter gives a higher performance compared to a 1/2” pipe diameter, and certainly the performances of both pipe sizes are improved when the supplied potential energy is increased. This innovative turbine has a maximum rotational speed at an optimum turbine diameter at 0.6m, accompanied by a point where there is a sudden reduction in the water flow rate, where previously the increment in the water flow rate was very high. This can shows from the outcome nomogram with 1” pipe diameter can perform 350 rpm speed with 1.48 L/sec water flow. The Z-Blade turbine has been examined and has shown good potential to be used for low-head (3m, 4m and 5m) and low-flow (less than 2.5 L/sec) conditions