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Cat's whiskers (Orthosiphon stamineus) leaves extracts were prepared using supercritical CO2 (SC-CO2) with full factorial design to determine the optimum extraction parameters. Nine extracts were obtained by varying pressure, temperature, and time. The extracts were analysed using FTIR, UV-Vis, and GC-MS. Cytotoxicity of the extracts was evaluated on human (colorectal, breast, and prostate) cancer and normal fibroblast cells. Moderate pressure (31.1 MPa) and temperature (60°C) were recorded as optimum extraction conditions with high yield (1.74%) of the extract (B2) at 60 min extraction time. The optimized extract (B2) displayed selective cytotoxicity against prostate cancer (PC3) cells (IC50 28 µg/mL) and significant antioxidant activity (IC50 42.8 µg/mL). Elevated levels of caspases 3/7 and 9 in B2-treated PC3 cells suggest the induction of apoptosis through nuclear and mitochondrial pathways. Hoechst and rhodamine assays confirmed the nuclear condensation and disruption of mitochondrial membrane potential in the cells. B2 also demonstrated inhibitory effects on motility and colonies of PC3 cells at its subcytotoxic concentrations. It is noteworthy that B2 displayed negligible toxicity against the normal cells. Chemometric analysis revealed high content of essential oils, hydrocarbon, fatty acids, esters, and aromatic sesquiterpenes in B2. This study highlights the therapeutic potentials of SC-CO2 extract of cat's whiskers in targeting prostate carcinoma.
RESUMEN
Purpose. To determine the neuroprotective properties of a latanoprost acid derivative (ACS67) that donates the gas hydrogen sulfide (H(2)S). Methods. Ischemia to the rat retina was induced by elevation of intraocular pressure. Electroretinograms (ERGs) were recorded and the retinas analyzed 2 days later by immunohistochemistry, Western blot analysis, and RT-PCR. Hydrogen peroxide (H(2)O(2)) was used to impose an insult on RGC-5 cells in culture. The nature of the insult to cultures was quantified by the resazurin-reduction assay procedure, staining for reactive oxygen species (ROS) and for apoptosis. ACS67, its sulfurated moiety (ACS1), and latanoprost were tested for both their toxicity and ability to blunt the negative effect of H(2)O(2) on RGC-5 cells. In addition, an assay was used to see whether any of the substances influenced glutathione (GSH) levels in RGC-5 cells. Results. Partial damage to the retina in situ after ischemia was characterized by an alteration of the ERG, a reduction in the retinal localization of specific antigens and a reduction and elevation of defined retinal proteins and mRNAs. Optic nerve axonal proteins were also drastically reduced by ischemia. Most of these changes were significantly blunted by an intravitreal injection of ACS67 directly after ischemia. ACS67, ACS1, and the antioxidant epigallocatechin gallate (EGCG) all stimulated GSH levels and significantly attenuated H(2)O(2)-induced toxicity to RGC-5 cells, whereas latanoprost did not. Conclusions. ACS67 acts as an H(2)S donor through its donating moiety ACS1 and as a consequence is able to act as a neuroprotectant.