Charles Gnanaraj

In vitro total phenolics, flavonoids contents and antioxidant activity of essential oil, various organic extracts from the leaves of tropical medicinal plant Tetrastigma from Sabah

OBJECTIVE To detect the in vitro total phenolics, flavonoids contents and antioxidant activity of essential oil, various organic extracts from the leaves of tropical medicinal plant Tetrastigma from Sabah. METHODS The dry powder leaves of Tetrastigma were extracted with different organic solvent such as hexane, ethyl acetate, chloroform, butanol and aqueous methanol. The total phenolic and total flavonoids contents of the essential oil and various organic extracts such as hexane, ethyl acetate, chloroform, butanol and aqueous ethanol were determined by Folin - Ciocalteu method and the assayed antioxidant activity was determined in vitro models such as antioxidant capacity by radical scavenging activity using α, α-diphenyl- β-picrylhydrazyl (DPPH) method. RESULTS The total phenolic contents of the essential oil and different extracts as gallic acid equivalents were found to be highest in methanol extract (386.22 mg/g) followed by ethyl acetate (190.89 mg/g), chloroform (175.89 mg/g), hexane (173.44 mg/g), and butanol extract (131.72 mg/g) and the phenolic contents not detected in essential oil. The antioxidant capacity of the essential oil and different extracts as ascorbic acid standard was in the order of methanol extract > ethyl acetate extract >chloroform> butanol > hexane extract also the antioxidant activity was not detected in essential oil. CONCLUSIONS The findings show that the extent of antioxidant activity of the essential oil and all extracts are in accordance with the amount of phenolics present in that extract. Leaves of Tetrastigma being rich in phenolics may provide a good source of antioxidant.

Antioxidative and chemopreventive effects of Nephrolepis biserrata against carbon tetrachloride (CCl4)-induced oxidative stress and hepatic dysfunction in rats.

Abstract Context: Nephrolepis biserrata L. (Nephrolepidaceae) has been used in folk medicine for protection against different diseases. Objective: The current research investigated the protective effect of the methanol extract of N. biserrata leaves against carbon tetrachloride (CCl4)-induced hepatic damage in rats. Materials and methods: Total phenolic content and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity were estimated. In addition, Sprague–Dawley (SD) rats were randomly divided into six groups: control, CCl4 (1.0 mg/kg b wt), N. biserrata extract (at doses of 125, 250, and 375 mg/kg b wt) with CCl4 and N. biserrata extract (at dose of 375 mg/kg b wt) alone. After 2 weeks all rats were sacrificed and hepatoprotective effect of N. biserrata was evaluated. Results: Our results indicated that the high total phenolic content (127.28 ± 1.57 mg GAE/g) of N. biserrata may be the major contributor to strong antioxidant activities. Moreover, N. biserrata significantly depleted the elevation of enzymatic levels of alanine aminotransferase and aspartate aminotransferase (20–93% recovery), reduced the extent of malondialdehyde (47–90% recovery), increased the level of reduced glutathione (25–39% recovery), and elevated the activities of catalase, glutathione reductase, glutathione peroxidase, glucose 6-phosphate dehydrogenase, glutathione S-transferase, and quinone reductase (5–34% recovery). Histopathological observations also revealed that N. biserrata decreased fatty degeneration and necrosis in CCl4 administered rats. Discussion and conclusion: N. biserrata has strong antioxidant activities and significant protective effects against CCl4 induced hepatotoxicity in rats.

Hepatoprotective effects of Flagellaria indica are mediated through the suppression of pro-inflammatory cytokines and oxidative stress markers in rats

Abstract Context The antioxidative properties of plants or plant derivative products are well known for their free radical scavenging effects. Flagellaria indica L. (Flagellariaceae) (FI) is a tropical medicinal plant used by the natives of Sabah as medication for semi-paralysis. Objective This study evaluates the hepatoprotective mechanism of FI against carbon tetrachloride (CCl4)-mediated liver damage. Materials and methods Aqueous extract of FI leaves was orally administered to adult Sprague–Dawley rats once daily for 14 consecutive days at 300, 400, and 500 mg/kg b.w. prior to CCl4 treatment (1.0 mL/kg b.w.) on the 13th and 14th days. Results Total phenolic content in the aqueous extract of FI leaves was 65.88 ± 1.84 mg gallic acid equivalent/g. IC50 value for free radical scavenging activity of FI aqueous extract was reached at the concentration of 400 μg/mL. Biochemical studies show that the aqueous extract of FI was able to prevent the increase in levels of serum transaminases, alanine aminotransferase, and aspartate aminotransferase (38–74% recovery), and malondialdehyde formation (25–87% recovery) in a dose-dependent manner. Immunohistochemical results evidenced the suppression of oxidative stress markers (4-hydroxynonenal and 8-hydroxydeoxyguanosine) and pro-inflammatory markers (tumour necrosis factor-α, interleukin-6, prostaglandin E2). Histopathological and hepatocyte ultrastructural alterations proved that there were protective effects in FI against CCl4-mediated liver injury. Signs of toxicity were not present in rats treated with FI alone (500 mg/kg b.w.). Discussion and conclusion It can be concluded that the presence of phenolic constituents and their antioxidative effects can be credited to the hepatoprotective activity of FI.

Hepatoprotective and Immunosuppressive Effect of Synedrella nodiflora L. on Carbon Tetrachloride (CCl4)-Intoxicated Rats.

Synedrella nodiflora is a medicinal plant that is used by the natives of Sabah, Malaysia to treat rheumatism and several other ailments. This study aims to evaluate the ability of the crude aqueous extract of S. nodiflora leaves to protect against carbon tetrachloride (CCl4)-mediated hepatic injury in rats. S. nodiflora aqueous extract was orally administered to adult Sprague Dawley rats once daily for 14 days (150 and 300 mg/kg body weight [b.w.]) before CCl4 oral treatment (1.0 mL/kg b.w.) on the 13th and 14th days. Serum alanine aminotransferase (ALT), serum aspartate aminotransferase (AST), hepatic antioxidant enzymes, and malondialdehyde (MDA) levels were estimated. Immunohistochemistry was performed for oxidative stress markers (4-hydroxynonenal [HNE], 8-hydroxy-deoxyguanosine [8-OHdG]) and proinflammatory markers (tumor necrosis factor-α, interleukin-6, prostaglandin E2). Biochemical, immunohistochemical, histological, and ultrastructural findings were in agreement to support the hepatoprotective effect of S. nodiflora against CCl4-mediated oxidative hepatic damage. Hepatoprotective effects of S. nodiflora might be attributable to the presence of phenolic antioxidants and their free radical scavenging property.

Pharmacological insights into antioxidants against colorectal cancer: A detailed review of the possible mechanisms

Colorectal cancer (CRC) is ranked as the fourth most lethal and commonly diagnosed cancer in the world according to the National Cancer Institutes latest report. Treatment methods for CRC are constantly being studied for advancement, which leads for more clinically effective cancer curing strategy. Patients with prolonged chronic inflammation caused by ulcerative colitis or similar inflammatory bowel disease are known to have high risks of developing CRC. But at a molecular level, oxidative stress due to reactive oxygen species (ROS) is an important trigger for cancer. Hence, in recent years, exogenous antioxidants have been immensely experimented in pre-clinical and clinical trials, considering it as a potential cure for CRC. Significantly, potential antioxidant compounds especially derivatives of medicinal plants have received great attention in the current research trend for CRC treatment. Though antioxidant compounds seem to have beneficial properties for the treatment of CRC, there are also limitations for pure compounds to be tested clinically. Therefore, this review aims to delineate the pharmacological awareness among researchers on using antioxidant compounds to treat CRC and the measures taken to prove the effectiveness of such compounds as impending drug candidates for CRC treatment in modern medication.

Toxicological and Pharmacological Use of Anticancer Compounds

Knowledge of medicinal plants from traditional medicinal drug therapy has brought limitless implications towards the discovery of novel compounds for modern therapeutic applications particularly for anticancer research. Research approaches have been taken for the development of traditional medicinal products into effective, non-toxic and clinically proven pharmaceuticals. Plant-derived anticancer compounds might exert adverse toxic effects in humans, depending on the species of plant, drug administration route, dose regimens and drug receptiveness. Due to this possibility, it is important to assess the toxicity profiles of new potential anticancer compounds through proper toxicological tests. The importance of preclinical toxicology studies is continually drifting from the use of conventional methods to assess the impending adverse effects of new anticancer agents over the past 10 years. Recent practice encompasses designing and carrying out more personalized agent-directed research within the framework of clinical pharmacology guidelines. Distinctive standpoints have been brought into view by clinical application of anticancer drugs that are apparent in their discovery and development. Evolving standards in estimating novel drug candidates through clinical and preclinical trials manifest the cytotoxic compound enhancements over time, with substantial aid from circumstances, and the current interest in discovering drug candidates with specifications on reaching targeted cells. This chapter highlights the relevance of plant-derived anticancer compounds through their pharmacological and toxicological uses.

Hepatoprotective mechanism of Lygodium microphyllum (Cav.) R.Br. through ultrastructural signaling prevention against carbon tetrachloride (CCl4)-mediated oxidative stress

Plants have been consumed in medicinal practices for centuries. Lygodium microphyllum (Cav.) R.Br. (Lygodiaceae), also known as Old World Climbing Fern, is a medicinal plant used by local communities in Sabah for skin and dysentery ailments. This study aims to test aqueous extract of L. microphyllum leaves for hepatoprotective and immunosuppressive activity in rats. Animal studies were carried out to evaluate hepatoprotection of aqueous extract of L. microphyllum at different doses (200, 400 and 600mg/kg b.w.) against carbon tetrachloride (CCl4)-mediated liver injury and histopathological alterations. Total phenolic content in aqueous extract of L. microphyllum leaves was 206.38±9.62mg gallic acid equivalent/g. The inhibitory concentration (IC50) for free radical scavenging activity of L. microphyllum was reached at a concentration of 65μg/ml.L. microphyllum was able to prevent the increase in levels of serum alanine aminotransferase, serum aspartate aminotransferase and hepatic malondialdehyde formation in a dose-dependent manner. Immunohistochemical results evidenced the suppression of oxidative stress markers (4-hydroxynonenal, 8-hydroxydeoxyguanosine) and pro-inflammatory cytokines (Tumor Necrosis Factor-α, Interleukin-6, Prostaglandin E2). Histopathological and hepatocyte ultrastructural alterations showed protective effects by L. microphyllum against CCl4-mediated oxidative stress. Hepatoprotective mechanism of L. microphyllum can be attributed to its antioxidative effects through protection of ultrastructural organelles.