| Description: |
Equisetin has antibacterial activity, the MIC's for Equisetin are 8 ug /mL against Bacillus subtilis, 16 ug /mL against Staphylococcus aureus and Methicillin Resistant Staphylococcus aureus (MRSA).Equisetin inhibits the DNP-stimulated ATPase activity of rat liver mitochondria and mitoplasts in a concentration-dependent manner; 50% inhibition is caused by about 8 nmol Equisetin/mg protein.It also specifically inhibits the substrate anion carriers of the mitochondrial inner membrane. |
| Targets: |
Calcium Channel | ATPase | Antifection | ROS |
| In vitro: |
| BMC Complement Altern Med. 2015 Jul 10;15:220. | | Antimicrobial activities of endophytic fungi obtained from the arid zone invasive plant Opuntia dillenii and the isolation of equisetin, from endophytic Fusarium sp.[Pubmed: 26160390] |
Opuntia dillenii is an invasive plant well established in the harsh South-Eastern arid zone of Sri Lanka. Evidence suggests it is likely that the endophytic fungal populations of O. dillenii assist the host in overcoming biotic and abiotic stress by producing biologically active metabolites. With this in mind there is potential to discover novel natural products with useful biological activities from this hitherto poorly investigated source. Consequently, an investigation of the antimicrobial activities of the endophytes of O. dillenii, that occupies a unique ecological niche, may well provide useful leads in the discovery of new pharmaceuticals.
METHODS AND RESULTS:
Endophytic fungi were isolated from the surface sterilized cladodes and flowers of O. dillenii using several nutrient media and the antimicrobial activities were evaluated against three Gram-positive and two Gram-negative bacteria and Candida albicans. The two most bioactive fungi were identified by colony morphology and DNA sequencing. The secondary metabolite of the endophyte Fusarium sp. exhibiting the best activity was isolated via bioassay guided chromatography. The chemical structure was elucidated from the ESIMS and NMR spectroscopic data obtained for the active metabolite. The minimum inhibitory concentrations (MICs) of the active compound were determined.
Eight endophytic fungi were isolated from O. dillenii and all except one showed antibacterial activities against at least one of the test bacteria. All extracts were inactive against C. albicans. The most bioactive fungus was identified as Fusarium sp. and the second most active as Aspergillus niger. The structure of the major antibacterial compound of the Fusarium sp. was shown to be the tetramic acid derivative, equisetin. The MIC's for equisetin were 8 μg mL(-1) against Bacillus subtilis, 16 μg mL(-1) against Staphylococcus aureus and Methicillin Resistant Staphylococcus aureus (MRSA).
CONCLUSIONS:
O. dillenii, harbors several endophytic fungi capable of producing antimicrobial substances with selective antibacterial properties. By producing biologically active secondary metabolites, such as equisetin isolated from the endophytic Fusarium sp., the endophytic fungal population may be assisting the host to successfully withstand stressful environmental conditions. Further investigations on the secondary metabolites produced by these endophytes may provide additional drug leads. |
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| In vivo: |
| J Bioenerg Biomembr. 1993 Oct;25(5):537-45. | | Effects of equisetin on rat liver mitochondria: evidence for inhibition of substrate anion carriers of the inner membrane.[Pubmed: 8132493] |
The effect of equisetin, an antibiotic produced by Fusarium equiseti, has been studied on mitochondrial functions (respiration, ATPase, ion transport).
METHODS AND RESULTS:
Equisetin inhibits the DNP-stimulated ATPase activity of rat liver mitochondria and mitoplasts in a concentration-dependent manner; 50% inhibition is caused by about 8 nmol equisetin/mg protein. The antibiotic is without effect either on the ATPase activity of submitochondrial particles or on the purified F1-ATPase. It inhibits both the ADP- or DNP-activated oxygen uptake by mitochondria in the presence of glutamate+malate or succinate as substrates, but only the ADP-stimulated respiration is inhibited if the electron donors are TMPD+ascorbate. It does not affect the NADH or succinate oxidation of submitochondrial particles. Equisetin inhibits in a concentration-dependent manner the active Ca(2+)-uptake of mitochondria energized both by ATP or succinate without affecting the Ca(2+)-uniporter itself. The antibiotic inhibits the ATP-uptake by mitochondria (50% inhibition at about 8 nmol equisetin/mg protein) and the Pi and dicarboxylate carrier. It does not lower the membrane potential at least up to 200 nmol/mg protein concentration.
CONCLUSIONS:
The data presented in this paper indicate that equisetin specifically inhibits the substrate anion carriers of the mitochondrial inner membrane. |
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