ABSTRACT
Background and Aim: Catnip essential oils have antimicrobial effects against bacteria, yeast, and fungi; however, there is limited information regarding their antimicrobial activity against pathogens that cause canine skin infections. This study aimed to identify the phytochemical constituents of catnip essential oil and assay its antimicrobial activity against Staphylococcus pseudintermedius, Malassezia pachydermatis, Microsporum canis, Microsporum gypseum, Microsporum gallinae, and Trichophyton mentagrophytes. Materials and Methods: Catnip essential oil was extracted by hydrodistillation, and its chemical constituents were analyzed by gas chromatography-mass spectrometry (GC-MS). In vitro antimicrobial activity was investigated using broth microdilution and time-kill tests. To evaluate the effect of catnip essential oil on microbial morphology and cell membrane integrity, scanning electron microscopy (SEM) and leakage studies were conducted. Results: GC-MS analysis revealed that the principal components of catnip essential oil were cis- and trans-nepetalactone (57.09% of peak area), trans-, cis-nepetalactone (39.69% of peak area), trans-caryophyllene (1.88% of peak area), and caryophyllene oxide (1.34% of peak area). The minimum inhibitory concentration, minimum bactericidal concentration, and minimum fungicidal concentration values determined by broth microdilution ranged from 0.0625 mg/mL to 4.0 mg/mL. Time-kill testing showed that the germicidal effects of catnip essential oil were time and concentration-dependent, respectively. Environmental SEM and cell leakage analysis indicated that catnip essential oil disrupted the integrity of cell membranes in the tested microorganisms. Conclusion: Catnip essential oil has potential as an alternative antimicrobial against a wide range of canine skin infection pathogens, including S. pseudintermedius, M. pachydermatis, Mi. canis, Mi. gypseum, Mi. gallinae, and T. mentagrophytes.
ABSTRACT
Andrographolide (Androg) has been reported to contain antiviral and antitumor activities, but the effects of Androg on human papillomavirus (HPV) infection and cervical cancer have not been elucidated. This study investigated the effects of Androg and its derivatives, namely, 14-deoxy-11,12-didehydroandrographolide (14-DDA) and 3,19-isopropylidene andrographolide (IPAD), on HPV16 pseudovirus (HPV16PsV) infectivity, HPV16 E6 oncogene expression and cervical cancer cell apoptosis. The result demonstrated that all compounds inhibited HPV16PsV infection and that 14-DDA showed the highest potency. Only Androg suppressed long control region (LCR) transcription activity of HPV16 in transiently transfected C33A cells and significantly inhibited E6 oncogene expression in SiHa cells in a dose-dependent manner. A twofold subcytotoxic concentration of IPAD exhibited an inhibitory effect on E6 oncogene expression at 48-h posttreatment. Interestingly, p53 protein was restored in a downstream process and was detected earlier by IPAD treatment than by Androg treatment. This result corresponded to the level of cell apoptosis and cell cycle arrest at the G2/M phase. E6 oncogene expression was also suppressed in CaSki cells treated with Androg and IPAD leading to cell apoptosis. These findings imply that Androg and its derivatives have different activities and may be effective agents for HPV prevention and cervical cancer treatment.
Subject(s)
Antiviral Agents/pharmacology , Diterpenes/pharmacology , Gene Expression Regulation, Viral/drug effects , Human papillomavirus 16/drug effects , Papillomavirus Infections/pathology , Uterine Cervical Neoplasms/virology , Apoptosis/drug effects , Cell Cycle/drug effects , Cell Line, Tumor , Cell Survival , Female , Humans , Oncogene Proteins, Viral/genetics , Oncogene Proteins, Viral/metabolism , RNA, Messenger/genetics , RNA, Messenger/metabolism , Repressor Proteins/genetics , Repressor Proteins/metabolism , Tumor Suppressor Protein p53/genetics , Tumor Suppressor Protein p53/metabolismABSTRACT
Andrographolide (AD), and 14-deoxyandrographolide (DAD) isolated from Andrographis paniculata Nees, Acanthaceae, and 3,19-isopropylideneandrographolide (IPAD), a semi-synthetic compound of AD, were examined for anti-HSV-1 activity in vitro. The inhibitory effects of these compounds on viral entry and replication steps were determined using pre- and post-infection assays, respectively. All the three compounds exhibited less than 50% inhibitory act against viral entry. In the post-infection, IPAD displayed absolute inhibition, whereas AD and DAD gave moderate activity. IPAD was selected to determine for the stage of anti-replication by time-of-addition and time-of-removal assays. From the time of removal assay, IPAD activity began after 4 h and completed at 16 h post infection which corresponded to the early genes expression. Its ability to inhibit HSV-1 was confirmed by polymerase chain reaction and the expression of viral glycoproteins C and D by western blot analysis. No viral enveloped glycoproteins D and C expressions were found. IPAD exhibited anti-HSV-1 replication relating to the early step of replication. Structure-activity relationships of andrographolide against HSV-1 was proposed, it is the first report of this ent-labdane diterpene.
