Mohd Nizam Mordi

In Vitro antioxidant and xanthine oxidase inhibitory activities of methanolic Swietenia mahagoni seed extracts.

This study examines the in vitro antioxidant activities of the methanol extract of Swietenia mahagoni seeds (SMCM seed extract). The extract was screened for possible antioxidant activities by free radical scavenging activity (DPPH), xanthine oxidase inhibition (XOI), hydrogen peroxide scavenging activity (HPSA) and ferric-reducing antioxidant power (FRAP) assays. The total phenolic and flavonoid contents were also determined. The extract exhibits antioxidant activity of 23.29% with an IC50 value of 2.3 mg/mL in the DPPH radical scavenging method, 47.2% in the XOI assay, 49.5% by the HPSA method, and 0.728 mmol/Fe(II)g in the FRAP method at the concentration tested. The amount of total phenolics and flavonoid contents was 70.83 mg gallic acid equivalent (GAE) and 2.5 ± 0.15 mg of catechin equivalent per gram of dry extract, respectively. High Performance Thin Layer Chromatography (HPTLC) screening indicates the presence of phenolic compounds in the SMCM seed extract. The results indicate that the extract has both high free radical scavenging and xanthine oxidase inhibition activity. The antioxidant activity of SMCM seed extract is comparable with that of other Malaysian tropical fruits and herbal plants.

In Vitro and in Vivo Effects of Three Different Mitragyna speciosa Korth Leaf Extracts on Phase II Drug Metabolizing Enzymes—Glutathione Transferases (GSTs)

In the present study, we investigate the effects of three different Mitragyna speciosa extracts, namely methanolic, aqueous and total alkaloid extracts, on glutathione transferase-specific activity in male Sprague Dawley rat liver cytosol in vitro and in vivo. In the in vitro study, the effect of Mitragyna speciosa extracts (0.01 to 750 µg/mL) against the specific activity of glutathione transferases was examined in rat liver cytosolic fraction from untreated rats. Our data show concentration dependent inhibition of cytosolic GSTs when Mitragyna speciosa extract was added into the reaction mixture. At the highest concentration used, the methanolic extract showed the highest GSTs specific activity inhibition (61%), followed by aqueous (50%) and total alkaloid extract (43%), respectively. In in vivo study, three different dosages; 50, 100 and 200 mg/kg for methanolic and aqueous extracts and 5, 10 and 20 mg/kg for total alkaloid extract were given orally for 14 days. An increase in GST specific activity was generally observed. However, only Mitragyna speciosa aqueous extract with a dosage of 100 mg/kg showed significant results: 129% compared to control.

Effect of Extraction Techniques on Phenolic Content, Antioxidant and Antimicrobial Activity of Bauhinia purpurea: HPTLC Determination of Antioxidants

Bauhinia purpurea leaf was extracted by Soxhlet, ultrasonication and maceration extraction methods using ethanol (99.5%, v/v) to obtain Soxhlet (SBE), ultrasonicated (UBE) and macerated (MBE) B. purpurea leaf extract. The effects of different extracting methods on the polyphenolic content and antioxidant activities using 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS), ferric-reducing antioxidant power (FRAP) and total antioxidant capacity (TAC) were investigated. Disc diffusion and broth dilution methods were also carried out to find the antibacterial activity of these extracts. Findings of this study showed that UBE possessed significant (P < 0.05) polyphenolic constituents followed by MBE and SBE. All the extracts exhibited good DPPH and ABTS radical scavenging as well as potential reducing ability in TAC and FRAP methods. UBE possessed significant (P < 0.05) radical scavenging activity and reducing ability followed by MBE and SBE. Even the results of antibacterial activity were similar to antioxidant activity, with UBE inhibiting most of the bacteria followed by MBE and SBE. All the extracts were subjected to thin layer chromatography (TLC) bioautography followed by high-performance TLC densitometric determination, and the results show that extraction using ultrasonication method yields the highest amount of antioxidant compounds among the three methods mentioned earlier. This study confirms ultrasonic extraction to be an ideal, simple and rapid method to obtain antioxidant- as well as antibacterial-enriched B. purpurea leaf extract. The HPTLC fingerprint profile can be used as a reference data for the standardisation of B. purpurea leaf.

Brine shrimp lethality and acute oral toxicity studies on Swietenia mahagoni (Linn.) Jacq. seed methanolic extract

Background: The seeds of Swietenia mahagoni have been applied in folk medicine for the treatment of hypertension, diabetes, malaria, amoebiasis, cough, chest pain, and intestinal parasitism. Here we are the first to report on the toxicity of the Swietenia mahagoni crude methanolic (SMCM) seed extract. Methods: SMCM seed extract has been studied for its brine shrimp lethality and acute oral toxicity, in mice. Results: The brine shrimp lethality bioassay shows a moderate cytotoxicity at high concentration. The LC50 for the extract is 0.68 mg/ml at 24 hours of exposure. The LD50 of the SMCM seed extract for acute oral toxicity in mice is greater than 5000 mg/kg. Conclusion: This study demonstrates that Swietenia mahagoni crude methanolic seed extract may contain bioactive compounds of potential therapeutic significance which are relatively safe from toxic effects, and can compromise the medicinal use of this plant in folk medicine.

Influence of sonication on the phenolic content and antioxidant activity of Terminalia catappa L. leaves.

Aim: This study was designed to evaluate the phenolic content and antioxidant activity of ethanolic extracts from T. catappa leaves obtained by different intervals of sonication. Methods: Three commonly used methods were followed to evaluate phenolic content and four in vitro methods like 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) radical scavenging assay, ferric reducing antioxidant potency (FRAP), and total antioxidant capacity assays for measuring the antioxidant activities. Antioxidant values of these assays were expressed in terms of milligrams vitamin C equivalent (VCE) antioxidant activities. Results: This study showed that extract obtained with 40 minutes of sonication possessed significant (P < 0.05) polyphenolic contents compared to 20 and 60 minutes sonication and control (24 hour maceration). Moreover, sonication of T. catappa leaf above 40 minutes was found to be unsuitable for extracting out phenolic contents. Even the results of antioxidant assays showed that 40 minutes of the sonicated extract exhibited significant (P < 0.05) VCE values compared to extracts obtained at different intervals of sonication and control. Conclusions: In sonication extraction method 40 minutes is an ideal time to obtain extract enriched with high polyphenolic content with good antioxidant activity from T. catappa leaves.

TLC–Bioautography-Guided Isolation, HPTLC and GC–MS-Assisted Analysis of Bioactives of Piper betle Leaf Extract Obtained from Various Extraction Techniques: In vitro Evaluation of Phenolic Content, Antioxidant and Antimicrobial Activities

The polyphenolic content, antioxidant and antibacterial activities of the ethanolic extracts of Piper betle leaf obtained from soxhlet (PBSx), sonication (PBSn) and maceration (PBMn) extraction methods were studied. GC–MS analysis was carried out to determine the variation in the phytoconstituents in these extracts. Whereas, thin-layer chromatography (TLC)–bioautography was conducted to localise, separate, and identify antioxidants, and their amount was determined by the newly developed high-performance thin-layer chromatography (HPTLC) method. The results of polyphenolic content, antioxidant assays and antimicrobial assay showed that PBSn contained significant amount of polyphenolics, antioxidant and antimicrobial activity followed by PBMn and PBSx. Moreover, the obtained antioxidant activity of PBSn was significant even in comparison with butylated hydroxytoluene (BHT) and commercially available grape seed extract (GRSx). In addition, GC–MS analysis shown marked variations in the amount of the phytoconstituents among all these extracts with PBSn containing higher amount followed by PBMn and PBSx. TLC bioautography resulted in the separation of three compounds which are identified as eugenol, allylpyrocatechol, and eugenyl acetate. The HPTLC densitometric determination was also supported the results of antioxidant assays by revealing the presence of higher amount of identified antioxidants in PBSn followed by PBMn and PBSx. Since, P. betle leaf extract has been used as one of the ingredients in several herbal formulations, results of this study will not only help the herbal industries in choosing the appropriate extraction technique but also the developed HPTLC method was simple, precise, sensitive and accurate hence can be utilised for the routine quality control and standardisation of formulations containing P. betle leaf extract.

Analgesic activity, toxicity study and phytochemical screening of standardized Cinnomomum iners leaves methanolic extract.

Cinnomomum iners standardized leaves methanolic extract (CSLE) was subjected to analgesic, toxicity and phytochemical studies. The analgesic activity of CSLE was evaluated using formalin, hot plate and tail flick tests at doses of 100, 200 and 500 mg/kg. CSLE showed significant activity (P < 0.05) in the formalin model (late phase) on the rats at doses of 200 and 500 mg/kg. However, CSLE did not show activity in the hot plate and tail flick tests. The results obtained suggest that CSLE acts peripherally to relieve pain. For the toxicity study, CSLE was orally administered to the Swiss albino mice according to the Organization for Economic Co-Operation and Development (OECD) guideline 423. There was no lethality or toxic symptoms observed for all the tested doses throughout the 14-day period. Phytochemical screening of CSLE showed the presence of cardiac glycoside, flavonoid, polyphenol, saponin, sugar, tannin and terpenoid.

Flavonoids-Rich Orthosiphon stamineus Extract as New Candidate for Angiotensin I-Converting Enzyme Inhibition: A Molecular Docking Study

This study aims to evaluate the in vitro angiotensin-converting enzyme (ACE) inhibition activity of different extracts of Orthosiphon stamineus (OS) leaves and their main flavonoids, namely rosmarinic acid (RA), sinensetin (SIN), eupatorin (EUP) and 3′-hydroxy-5,6,7,4′-tetramethoxyflavone (TMF). Furthermore, to identify possible mechanisms of action based on structure–activity relationships and molecular docking. The in vitro ACE inhibition activity relied on determining hippuric acid (HA) formation from ACE-specific substrate (hippuryl-histidyl-leucine (HHL)) by the action of ACE enzyme. A High Performance Liquid Chromatography method combined with UV detection was developed and validated for measurement the concentration of produced HA. The chelation ability of OS extract and its reference compounds was evaluated by tetramethylmurexide reagent. Furthermore, molecular docking study was performed by LeadIT-FlexX: BioSolveIT’s LeadIT program. OS ethanolic extract (OS-E) exhibited highest inhibition and lowest IC50 value (45.77 ± 1.17 µg/mL) against ACE compared to the other extracts. Among the tested reference compounds, EUP with IC50 15.35 ± 4.49 µg/mL had highest inhibition against ACE and binding ability with Zn (II) (56.03% ± 1.26%) compared to RA, TMF and SIN. Molecular docking studies also confirmed that flavonoids inhibit ACE via interaction with the zinc ion and this interaction is stabilized by other interactions with amino acids in the active site. In this study, we have demonstrated that changes in flavonoids active core affect their capacity to inhibit ACE. Moreover, we showed that ACE inhibition activity of flavonoids compounds is directly related to their ability to bind with zinc ion in the active site of ACE enzyme. It was also revealed that OS extract contained high amount of flavonoids other than RA, TMF, SIN and EUP. As such, application of OS extract is useful as inhibitors of ACE.

Unexpected Reduction of Indole Double Bond in Mitragynine Using n-Butylsilane and Catalytic Tris(pentaflorophenyl)borane

Abstract An unexpected reduction of indolic double bond of mitragynine was described by using n-butyl silane and tris(pentafluorophenyl)triborane. GRAPHICAL ABSTRACT

Site-directed fragment-based generation of virtual sialic acid databases against influenza A hemagglutinin.

In this study fragment-based drug design is combined with molecular docking simulation technique, to design databases of virtual sialic acid (SA) analogues with new substitutions at C2, C5 and C6 positions of SA scaffold. Using spaces occupied by C2, C5 and C6 natural moieties of SA when bound to hemagglutinin (HA) crystallographic structure, new fragments that are commercially available were docked independently in all the pockets. The oriented fragments were then connected to the SA scaffold with or without incorporation of linker molecules. The completed analogues were docked to the whole SA binding site to estimate their binding conformations and affinities, generating three databases of HA-bound SA analogues. Selected new analogues showed higher estimated affinities than the natural SA when tested against H3N2, H5N1 and H1N1 subtypes of influenza A. An improvement in the binding energies indicates that fragment-based drug design when combined with molecular docking simulation is capable to produce virtual analogues that can become lead compound candidates for anti-flu drug discovery program.