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Volatile oils are natural compounds that can be adopted in many drug and cosmetic formulations. Many volatile oils can be extracted from natural plants and they have their own special biological activities. Nine volatile oils including pine oil (P), guava leaf oil (G), lime peel oil (L), cinnamon bark oil (C), sage oil (S), tea tree oil (T) rosemary oil (R), clove oil (CL) and jasmine sambac oil (J) were in vitro tested for anti-microbial activities against various microbes and cytotoxicity properties agianst HCT116 and HT29 cell lines. From our result, for antimicrobial activities, the most effective oil against Gram positive such as Staphylococcus aureus are T, R and L. Only P showed the great inhibition on Gram negative bacteria such as Escherichia coli. C, P, L, T and R also exhibited different inhibitory effects on the pathogenic yeasts depending on the candida species. For the antitumoral activity on colorectal cancer cell lines, C showed the most cytotoxicity on both HCT116 and HT29 cells with IC50 value of 7.7 and 74.0 μg/ml, respectively. The second most cytotoxic was guava oil with the IC50 of 101.2 and 97.91 μg/ml on HCT116 and HT29, respectively. These investigated data may be useful as information for oil selection and development of pharmaceutical dosage forms using these natural volatile oils as the ingredients.

Cinnamon bark oil (CO) has anticancer activity in various type of cancer cells and could be used alternatively to support anticancer drugs. For the enhancement of cytotoxic effects, the combination of bioactive compounds with chemotherapeutics drug has been interested in the possibility of cancer treatment. This study aimed to determine whether there is a synergistic effect between the combination of CO and chemotherapeutic drug such as imatinib mesylate (IM) on HCT 116 and HT29 colorectal cancer cell lines. The cytotoxic activities of CO and IM were investigated individually and their combination in each cancer cell line using cell viability assay. The interaction between CO and IM was determined using the combination index (CI) method. Cinnamon bark oil exhibited the high cytotoxicity on HCT116 cell, while IM showed the high cytotoxic activity on HT 29 cell. The tested combination decreased notably viability of cell and allowed to reduce the dose of imatinib chemotherapy drug. The combination of CO with IM showed a strong synergistic effect (CI < 1) on HT29 cell. For HCT116 cell treated combination of CO (4μg/mL) and IM (10μg/mL) demonstrated a strong synergistic effect (CI = 0.52). Thus, the combined CO and IM might be applied for pharmaceutical drug delivery for colon cancer treatment.

Natural resins such as benzoin, propolis and rosin have been widely employed in the pharmaceuticals. In this study, in situ forming gels (ISG) were prepared using natural resins as matrix forming agents to deliver vancomycin hydrochloride (VH) for periodontitis treatment. The formulations were investigated for their physicochemical properties, drug release and antimicrobial activities. Transformation from a solution to a solid matrix was achieved after the formulas were exposed to a simulated crevicular fluid. The rate of resin matrix formation was found to decrease with time and became more opaque owing to gradual phase separation with resin network formation. They flowed with pseudo-plastic behavior and provided appropriate injectability as well as good mechanical properties. Sustained VH release was attained for a 5-day period. VH-loaded natural resin ISGs inhibited against Staphylococcus aureus, Porphyromonas gingivalis, Candida albicans, and Streptococcus mutans. Natural resin-based ISGs comprising of propolis or benzoin showed a more effective delivery of VH than that of rosin. Thus, VH-loaded benzoin and propolis ISGs were found to have a possible application for infected periodontitis treatment.

Imatinib mesylate (IM) is a kinase inhibitor with inhibitory effect on colon cancer cell proliferation. However, some adverse effect of imatinib and drug resistance are challenges for maintenance the therapeutic effect with lowering the dose; thus, the combination with other substances was of interest. Gambogic acid (GA), a natural compound from gamboge, was revealed for inhibition of cell proliferation in many types of cancers. This research aimed to investigate the effect of GA on IM response in colorectal cancer cells, HT29 and HCT116. The 50% inhibitory concentration (IC50) of IM and GA was determined. Concentrations which lower than IC50 of each compound were combined and tested for the combination effects on HT29 and HCT116 cells. The results were analyzed using isobologram to assess the types of interaction. The combination index (CI) of the tests was calculated at the 3 different percentages of inhibition (IC50, IC60 and IC70). The finding indicated that IC50 and IC60 of the combination of 5 and 7 μM IM with 0.2-1.2 μM GA showed antagonism while IC70 showed additive effect in HT29 cell line. In HCT116 cell line, IC50 of 10 μM IM with 0.1-0.8 μM GA showed antagonism while IC60 and IC70 expressed additive effect. For the studies with IC50 and IC60 of 12 μM IM with 0.1-0.8 μM GA showed antagonistic result while IC70 showed additive effect. The result indicated that, at the lower IC studied, the CI obtained from the experiments indicated the inhibitory effects, while the higher IC, the results showed the changing trend from antagonistic to additive and synergistic effects of GA on IM.

The in situ forming gel (ISG) has been developed as a controlled drug delivery system to prolong drug release. This study aims to prepare ISG system based on gamboge resin (GB) as matrix former. The various amounts of GB dissolving in dimethyl sulfoxide (DMSO) and N-methyl pyrrolidone (NMP) were used to obtain the ISG systems and evaluated for their pH, viscosity, injectability and matrix forming. The antimicrobial activities against three strains of Staphylococcus aureus including the Methicilin Resistant S. aureus (MRSA) and Porphyromonas gingivalis were conducted. GB ISG systems exhibited good injectability with low viscosity. GB in DMSO showed a faster transformation to solid matrix compared to that in NMP. The gambogic acid (GA) content in crude GB was 33.70 ± 0.13%. The sustainable GA release from GB ISG could be attained. Thus, GB ISG exhibits the potential application as a drug delivery system for active compounds and is enable for using as a therapeutic dosage form owing to its antimicrobial activity.

Background: Colorectal cancer is a common cause of cancer-related deaths Epigenetic regulation of the influx sodium dependent monocarboxylate transporter-1 )SMCT1), a tumor suppressor, was recognized in colorectal cancer. In this study, effects of Curcumin (Cur), on SMCT1 gene expression was determined. A low SMCT1 expression, HCT116, cell line was used to test an in vitro effect of Cur on epigenetic regulation of SMCT1 expression via DNA methylation and its function. It was hypothesized that Cur can induce SMCT1 expression in the cells via hypomethylation effect. Measurement of increase in SMCT1 function was performed using dichloroacetate (DCA), a cytotoxic substrate of SMCT1. Methods: The effect of 5′Azacytidine (Aza), a hypomethylating agent, and Cur on SMCT1 expression and function was determined. Cells were treated with Aza and various concentrations of Cur for 72 h. After that SMCT1 expression was determined by real time PCR and Western blotting. To evaluate the SMCT1 function, DCA was used in MTT assay. Results: After treatment with 40 µM Cur, SMCT1 mRNA was significantly increased (p < 0.05). This was correlated with SMCT1 protein expression. Cells treated with 40 µM of Cur showed significant increase of cytotoxicity at DCA concentrations of 25 (p < 0.001) and 12.5 mM (p