Protective effects of Thai Mucuna pruriens (L.) DC. var. pruriens seeds on sexual behaviors and essential reproductive markers in chronic unpredictable mild stress mice.

Background and aims: Chronic stress is a major common cause of male infertility. Many species of velvet beans are shown to be rich in l-DOPA. In Thai folklore medicine, seeds of Mucuna pruriens (L.) DC. var. pruriens (Thai Mhamui or T-MP) have been used for treating erectile dysfunction. This study aimed to determine l-DOPA levels in T-MP seed extract and investigate its preventive on sexual behaviors and reproductive parameter damages including essential proteins in chronic unpredictable mild stress (CUMS) mice. Experimental procedure: Mice were divided into 4 groups: (I) control, (II) CUMS, (III) T-MP300 + CUMS, and (IV) T-MP600 + CUMS. Groups I and II received DW while groups III and IV were pretreated with the seed extracts (300 and 600 mg/kg BW) for 14 consecutive days before co-treatment with a randomly different CUMS/day (from 12 mild stressors) for 43 days. Results and conclusion: T-MP seed extract contained l-DOPA approximately 10% of total dried weight. A dose of 600 mg/kg improved sexual performances and degenerative seminiferous epithelium in CUMS mice. Sperm qualities and testosterone level were elevated while corticosterone was decreased in co-treatment groups. T-MP-CUMS cotreated groups also improved expressions of AKAP4, AR, and TyrPho proteins in testis, epididymis, and sperm. T-MP increased StAR and CYP11A1 expressions in testis. It also suppressed testicular apoptosis via decreased expressions of Hsp70, caspases 3, and 9. T-MP seeds containing l-DOPA could improve sexual behaviors and essential reproductive proteins caused by CUMS. Section: Natural Products. Taxonomy classification by evise: Traditional Herbal Medicine; Animal Model; Histopathology.

Active site binding modes of curcumin in HIV-1 protease and integrase.

Structure models for the interaction of curcumin with HIV-1 integrase (IN) and protease (PR) were investigated using computational docking. Curcumin was found to bind preferentially in similar ways to the active sites of both IN and PR. For IN, the binding site is formed by residues Asp64, His67, Thr66, Glu92, Thr93, Asp116, Ser119, Asn120, and Lys159. Docked curcumin contacts the catalytic residues adjacent to Asp116 and Asp64, and near the divalent metal (Mg2+). In the PR docking, the curcumin structure fitted well to the active site, interacting with residues Asp25, Asp29, Asp30, Gly27', Asp29', and Asp30'. The results suggest that o-hydroxyl and/or keto-enol structures are important for both IN and PR inhibitory actions. The symmetrical structure of curcumin seems to play an important role for binding to the PR protein, whereas the keto-enol and only one side of the terminal o-hydroxyl showed tight binding to the IN active site.

Manganese complexes of curcumin analogues: evaluation of hydroxyl radical scavenging ability, superoxide dismutase activity and stability towards hydrolysis.

In order to improve the antioxidant property of curcumin and its analogue, diacetylcurcumin, manganese was incorporated into the structures in order to enhance superoxide dismutase (SOD) activity. Manganese (Mn) complexes of curcumin (CpCpx) and diacetylcurcumin (AcylCpCpx) were synthesized and firstly investigated for SOD activity and hydroxyl radical (HO*) scavenging ability. SOD activity was evaluated by both the nitroblue tetrazolium (NBT) reduction assay and electron paramagnetic resonance (EPR) with 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) as a spin trapping agent. CpCpx and AcylCpCpx inhibited the NBT reduction and decreased the DMPO/OOH adduct much greater than corresponding antioxidants or ligands, with IC50 values of 29.9 and 24.7 microM (NBT), and 1.09 and 2.40 mM (EPR), respectively. For EPR, potassium superoxide (KO2) was used as a source of O2- where qualitative results suggested that CpCpx and AcylCpCpx were SOD mimics, which catalyze the conversion of O2- to dioxygen and hydrogen peroxide (H2O2). Additionally, CpCpx and AcylCpCpx exhibited the great inhibition of DMPO/OH adduct formation with an IC50 of 0.57 and 0.37mM, respectively, which were comparable to that of curcumin (IC50 of 0.64 mM), indicating that both Mn complexes are also an effective HO* scavenger. The stability against hydrolysis in water, various buffers and human blood/serum was carried out in vitro. It was found that both Mn complexes were pH and salt concentration dependent, being more stable in basic pH. In the human blood/serum test, CpCpx was more stable against hydrolysis than AcylCpCpx with about 10 and 20% of free Mn2+ releasing, respectively.

NAD(P)H:quinone oxidoreductase 1: role as a superoxide scavenger.

Experiments using purified recombinant human NAD(P)H:quinone oxidoreductase 1 (NQO1) revealed that the auto-oxidation of fully reduced protein resulted in a 1:1 stoichiometry of oxygen consumption to NADH oxidation with the production of hydrogen peroxide. The rate of auto-oxidation of fully reduced NQO1 was markedly accelerated in the presence of superoxide (O(2)(*)(-)), whereas the addition of superoxide dismutase greatly inhibited the rate of auto-oxidation. The ability of reduced NQO1 to react with O(2)(*)(-) suggested a role for NQO1 in scavenging O(2)(*)(-), and this hypothesis was tested using established methods for O(2)(*)(-) production and detection. The addition of NQO1 in combination with NAD(P)H resulted in inhibition of dihydroethidium oxidation, pyrogallol auto-oxidation, and elimination of a potassium superoxide-generated ethoxycarbonyl-2-methyl-3,4-dihydro-2H-pyrrole-1-oxide:O(2)(*)(-) adduct signal (electron spin resonance). Kinetic parameters for the reduction of O(2)(*)(-) by NQO1 were estimated using xanthine/xanthine oxidase as the source of O(2)(*)(-) and after NQO1-dependent NADH oxidation at 340 nm. The ability of NQO1 to scavenge O(2)(*)(-) was also examined using cell sonicates prepared from isogenic cell lines containing no NQO1 activity (NQO1(-)) or very high levels of NQO1 activity (NQO1(+)). We demonstrated that addition of NAD(P)H and cell sonicate from NQO1(+) but not NQO1(-) cells resulted in an increased level of O(2)(*)(-) scavenging could be inhibited by 5-methoxy-1,2-dimethyl-3-[(4-nitrophenoxy)methyl]indole-4,7-dione (ES936), a mechanism-based inhibitor of NQO1. NQO1 can generate hydroquinones that are redox active, and the O(2)(*)(-) scavenging activity of NQO1 may allow protection against O(2)(*)(-) at the site of hydroquinone generation. In addition, the O(2)(*)(-) scavenging activity of NQO1 may provide an additional level of protection against O(2)(*)(-) induced toxicity.

Manganese complexes of curcumin and its derivatives: evaluation for the radical scavenging ability and neuroprotective activity.

In this study, three manganese complexes of curcumin (Cp) and related compounds, diacetylcurcumin (AcylCp) and ethylenediamine derivative (CpED), were synthesized and evaluated in vitro for antilipid peroxidation and superoxide dismutase activity. The manganese complexes exhibited a great capacity to protect brain lipids against peroxidation with IC50 of 6.3-26.3 microM. All manganese complexes showed much greater SOD activity than their corresponding antioxidant ligands as well as trolox with IC50 values of 8.9-29.9 microM. AcylCp and curcumin manganese complexes (AcylCpCpx and CpCpx) also gave the highest inhibitory activity to H2O2-induced cell damage (oxidative stress) at 0.1 microg/ml (< 0.2 microM) in NG108-15 cells, which were more potent than curcumin and related compounds. The neuropharmacological tests in mice supported the idea that the SOD mimicking complexes were able to penetrate to the brain as well as their role in the modulation of brain neurotransmitters under the aberrant conditions. The complexes significantly improved the learning and memory impairment induced by transient ischemic/reperfusion. AcylCpCpx, CpCpx, and CpEDCpx showed significant protection at 6.25, 25, and 50 mg/kg (i.p.), respectively, whereas manganese acetate and curcumin had no effect at doses of 50 mg/kg. In addition, treatment of AcylCpCpx and curcumin significantly attenuated MPTP-induced striatal dopamine depletion in mice, which was in accordance with the increase in the density of dopaminergic neurons when compared with MPTP-treated mice. These results support the important role of manganese in importing SOD activity and consequently, the enhancement of radical scavenging activity. AcylCpCpx and CpCpx seem to be the most promising neuroprotective agents for vascular dementia.

Manganese-based complexes of radical scavengers as neuroprotective agents.

Manganese was incorporated in the structure of the selected antioxidants to mimic the superoxide dismutase (SOD) and to increase radical scavenging ability. Five manganese complexes (1-5) showed potent SOD activity in vitro with IC(50) of 1.18-1.84 microM and action against lipid peroxidation in vitro with IC(50) of 1.97-8.00 microM greater than their ligands and trolox. The manganese complexes were initially tested in vivo at 50 mg/kg for antagonistic activity on methamphetamine (MAP)-induced hypermotility resulting from dopamine release in the mice brain. Only manganese complexes of kojic acid (1) and 7-hydroxyflavone (3) exhibited the significant suppressions on MAP-induced hypermotility and did not significantly decrease the locomotor activity in normal condition. Manganese complex 3 also showed protective effects against learning and memory impairment in transient cerebral ischemic mice. These results supported the brain delivery and the role of manganese in SOD activity as well as in the modulation of brain neurotransmitters in the aberrant condition. Manganese complex 3 from 7-hydroxyflavone was the promising candidate for radical implicated neurodegenerative diseases.