Methanol extract of Melastoma malabathricum leaves inhibited the growth of Staphylococcus aureus and six clinical isolates of Methicilin Resistant Stapyhlococcus aureus (MRSA 1-6). The minimum inhibitory concentration (MIC) of test substance was 1.565mg/ml and the minimum bacteriocidal concentration (MBC) was 3.125 mg/ml. The methanol extract suppressed RNA synthesis at 10 mg/ml as shown by RNA profile which was devoid of three bands compared to the control. Reverse transcriptase-polymerase chain reaction (RT-PCR) analysis using seven primer pairs was only successful in amplifying four cDNA amplicons. The failure to amplify three cDNA amplicons for three primer pairs corresponding to gyrA, femA and nuc genes, implied the possibility of suppression of the corresponding mRNA. Electrophoretic separation of endogenous and exogenuos bacterial proteins showed that three and five protein, respectively were not expressed. One endogenous and three exogenous proteins were over-expressed in treated MRSA compared with untreated control. The results of the molecular and proteomic analyses are in agreement, and based on primers being used, methanol extract of M. malabathricum leaves possibly inhibits MRSA growth through inhibition of DNA synthesis, peptidoglycan production, and nuclease production.
Keywords: Methicillin resistant Staphylococcus aureus; Melastoma malabathricum; gene expression; protein production
Ochrosia oppositifolia can be found along the coastline and is locally known as 'Mempelam pasih' or 'Mangga laut'. In this study, the alkaloids from the leaves, stem-bark and roots were extracted and tested for their antibacterial activity. So far, no previous studies have been carried out to determine the antibacterial potential of the extracts. Each extract was tested using disc-diffusion and minimum inhibitory concentration (MIC) methods. The highest inhibitory diameters shown by 10 mg/mL extracts of the leaves and stem-bark against Staphylococcus aureus and the roots against MRSA were 10.0±2.8 and 10.5±2.1 and 14.0±2.8 mm. On the other hand, the MIC values exhibited by the leaf and stem-bark extracts against Bacillus subtilis, Salmonella thyphimurium and Serratia marcescens and the root extract against Vibrio fluvialis were 3.75 and 0.94 and 0.12 mg/mL. This study broadens the bioactivity potential of the plant and the information obtained can be utilized for pharmacological purposes.
Polyalthia cinnamomea Hook.f. & Thomson (Annonaceae) or locally known as ‘Larak Batu Bukit’, ‘Pisang-pisang’,
‘Sugao’ and ‘Sigumpet Hutan’ is a small woody plant found throughout Malaysia and Singapore. In this study, the
basic chemical components from the leaves of the plant were fractionated and the antibacterial activity as well
as the major constituents of the basic fraction was determined. To the best of our knowledge, this is the first study
being carried out on the bioactivity and phytochemistry of P. cinnamomea. The basic fraction remarkably inhibited
the growth of ten bacteria tested except one. The biggest inhibitory diameter and the lowest minimum inhibitory
concentration were 19.0±4.6 mm and 0.125 mg/mL against respective Bacillus subtilis and Bacillus thuringiensis.
Gas chromatography-mass spectrometry (GCMS) analysis of the basic fraction identified four major cyclosiloxanes
of octamethylcyclotetrasiloxane (18.1%), decamethylcyclopentasiloxane (16.4%), dodecamethylcyclohexasiloxane
(14.1%) and tetradecamethylcycloheptasiloxane (6.0%). The knowledge of the antibacterial potential of P. cinnamomea
basic fraction and the major constituents present in the fraction can be utilized in the fields of natural products,
pharmaceutical, cosmetic and personel care industries.
Kajian ini bertujuan untuk melakukan penyaringan pelbagai aktiviti biologi menggunakan ekstrak akues rebusan air, ekstrak metanol larut air, ekstrak etanol, ekstrak metanol dan polisakarida miselium cendawan Amauroderma sp. yang diperoleh dari Taman Negeri Royal Belum. Ujian antikanser, antivirus, antibakteria dan antioksida digunakan dalam penyaringan ini. Ujian antikanser dijalankan ke atas sel kanser ovari (CaOV-3) dan sel normal hati Chang dengan tamoxifen digunakan sebagai kawalan. Kesemua nilai IC50 yang diperoleh menunjukkan nilai yang tinggi (400±3.6 - 3950±0.005 μg/mL). Sementara itu, kajian awal penyaringan aktiviti antivirus dimulakan dengan ujian sitotoksisiti ekstrak terhadap sel Vero. Didapati hanya ekstrak rebusan air dan etanol memberi nilai CC50 masing-masing pada kepekatan 6.4±0.3 dan 7.9±1.28 mg/mL. Seterusnya, ujian antivirus menggunakan virus Herpes Simpleks Jenis 1 (HSV-1) yang menjangkiti sel Vero dilakukan dengan dua kaedah iaitu pra-rawat dan pos-rawat. Ekstrak menunjukkan aktiviti yang tidak ketara terhadap HSV-1 bagi kedua-dua kaedah ini. Penyaringan aktiviti antibakteria dilakukan ke atas beberapa jenis bakteria gram negatif dan positif dengan satu siri kepekatan ekstrak; 10, 5, 2.5, 1.25 dan 0.625 mg/mL. Kesemua ekstrak tidak menunjukkan aktiviti antibakteria berdasarkan ketiadaan sebarang zon perencatan dalam kesemua piring petri. Walau bagaimanapun, penyaringan antioksida menunjukkan kadar peratusan penyingkiran radikal bebas yang tinggi terutamanya ekstrak etanol iaitu 93.6%. Ini diikuti oleh ekstrak rebusan air (92.65%), metanol (88.83%) serta polisakarida (85.75%). Memandangkan kesemua ekstrak tidak menunjukkan kehadiran aktiviti sitotoksik, antivirus dan antibakteria, tetapi mempunyai aktiviti antioksida yang signifikan, maka bolehlah disimpulkan bahawa pelbagai ekstrak Amauroderma sp. sangat berpotensi secara khusus sebagai komponen nutrisi bersifat antioksidatif.
Chromatographic purification of chloroform extract of the twigs of Ellipeia cuneifolia has led to the discovery of three compounds comprising of 2´,4´-dihydroxy-4,6´-dimethoxychalcone; tepanone; and O-methylmoschatoline. Structures of the compounds were established by interpreting their spectral data and by comparing them with those of the literature. Two of them showed antibacterial activities.
A phytochemical study was conducted on the stems and leaves of Hedychium malayanum (Zingiberaceae). Three steroids
namely stigmasterol (1), sitostenone (2) and stigmast-4-ene-3,6-dione (3) as well as one triterpene, lupenone (4) and
one oxygenated sesquiterpene, caryophyllene oxide (5) were successfully isolated from the respective stems and leaves,
utilizing several chromatographic techniques. Their structures were elucidated by spectroscopic means (IR, MS, NMR),
and by comparison with the literature data.
The present study was aimed at determining the compounds available in Eleusine indica methanol extract and the effects on
herpes simplex virus type 1 (HHV1) replication cycle and progeny infectivity. Twelve compounds mostly from the flavonoid
and phenolic groups were identified by Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS) analysis. The
effect on replication phases of HHV1 was determined by time-of-addition, time-removal and virus yield reduction assays
with expression of selected genes analysed by quantitative Real Time-Polymerase Chain Reaction (qRT-PCR). The extract
inhibited plaque formation the most during the first 2 h and at 24 h of infection. Plaque formation inhibition was also
noted at all other time points but at lesser percentage. Treatment with E. indica reduced progeny infectivity when treated
for 10 h and was dose-dependent. E. indica methanol extract inhibited immediate early, early and late phases of HHV1
replication cycle by modifying the expression of UL
54, UL
27 and UL
30 genes during the infection. Immunostaining of
infected cells confirmed that E. indica inhibited mainly Glycoproteins B but not Glycoprotein C and D. Thus, the methanol
extract of E. indica has the ability to alter HHV1 replication cycle at almost all stages and reduce progeny infectivity.
A study was conducted to investigate the antiviral activity of aqueous extracts from Orthosiphon stamineus (OS).
Extraction was done using different parts of OS. The whole plant except root (WPOS), leaves (LOS) and flowers (FOS) of
OS were extracted using aqueous extraction method. Cytotoxicity was assessed using 3-(4,5-dimethylthiazol-2,5-diphenyl
tetrazolium bromide (MTT) assay. Plaque reduction assays were carried out to evaluate the antiviral activity of OS extract
against herpes simplex virus type 1 (HSV-1). These include post-treatment, pre-treatment and virucidal assays. High
antiviral activity was observed in post-treatment and virucidal assay with 100% reduction of HSV-1 plaque at 0.39 mg/
mL in LOS, FOS and WPOS. In pre-treatment assay, 79%, 84% and 97% plaque reduction using the same concentration
was observed in FOS, LOS and WPOS, respectively. In conclusion, this study showed that OS aqueous extract has promising
potential to be explored as anti-HSV-1 agent regardless of the mode of treatment.