Sidgi S. Hasson

Antimicrobial, antioxidant and cytotoxic activities and phytochemical screening of some yemeni medicinal plants.

The traditional medicine still plays an important role in the primary health care in Yemen. The current study represents the investigation of 16 selected plants, which were collected from different localities of Yemen. The plants were dried and extracted with two different solvents (methanol and hot water) to yield 34 crude extracts. The obtained extracts were tested for their antimicrobial activity against three Gram-positive bacteria, two Gram-negative bacteria, one yeast species and three multiresistant Staphylococcus strains using agar diffusion method, for their antioxidant activity using scavenging activity of DPPH radical method and for their cytotoxic activity using the neutral red uptake assay. In addition, a phytochemical screening of the methanolic extracts was done. Antibacterial activity was shown only against Gram-positive bacteria, among them multiresistant bacteria. The highest antimicrobial activity was exhibited by the methanolic extracts of Acalypha fruticosa, Centaurea pseudosinaica, Dodonaea viscosa, Jatropha variegata, Lippia citriodora, Plectranthus hadiensis, Tragia pungens and Verbascum bottae. Six methanolic extracts especially those of A. fruticosa, Actiniopteris semiflabellata, D. viscosa, P. hadiensis, T. pungens and V. bottae showed high free radical scavenging activity. Moreover, remarkable cytotoxic activity against FL-cells was found for the methanolic extracts of A. fruticosa, Iris albicans, L. citriodora and T. pungens. The phytochemical screening demonstrated the presence of different types of compounds like flavonoids, terpenoids and others, which could be responsible for the obtained activities.

Antisnake Venom Activity of Hibiscus aethiopicus L. against Echis ocellatus and Naja n. nigricollis

The objective of the study is to investigate whether the Hibiscus aethiopicus L. plant has neutralization activity against venoms of two clinically important snakes. The H. aethiopicus was dried and extracted with water. Different assays were performed to evaluate the plants acute toxicity and its anti-snake venom activities. The results showed that H. aethiopicus extract alone had no effect on the viability of C2C12 muscle cells, but significantly (P < .05) protected muscle cells against the toxic effects of E. ocellatus venom at 55, 150, and 300 μg/mL. The maximum protective effect of the extract was exhibited at 75 μg/mL. The extract significantly (P < .001) inhibited the cytotoxic effects of E. ocellatus venom at 300 μg/mL. All rabbits (n = 10) and guinea pigs (n = 10) were alive after the two weeks of given the lethal dosage 16 g/Kg of the H. aethiopicus extract herbal solution. No abnormal behaviour was observed of both groups of animals. All guinea pigs (n = 3) treated with venoms alone (5 mg/kg) died. However, all guinea pigs (n = 21) treated with venom (5 mg/kg) and the extract (400 to 1000 mg/kg) survived. Guinea pigs (n = 3) treated with Naja n. nigricollis venom alone (2.5 mg/kg) and guinea pigs (n = 21) venom with the extract (400 to 1000 mg/kg) died. The H. aethiopicus completely (100%) blocked the haemorrhagic activity of E. ocellatus in the egg embryo at 3.3 mg/mL of extract. These findings suggest that H. aethiopicus may contain an endogenous inhibitor of venom-induced haemorrhage.

In vitro antibacterial activity of three medicinal plants-Boswellia (Luban) species

Objective To study in vitro antibacterial and antifungal activity of hot water and methanolic extracts of the three medicinal plants- Boswellia (Luban) species. Methods Three selected plants were collected from different localities of Soqotra (Republic of Yemen), Dohfar (Sultanate of Oman) and Republic of Somalia. The plants were dried and extracted with two different solvents (methanol and hot water) to yield six crude extracts. The obtained extracts were tested for their antibacterial activity against eleven different bacterial strains and two fungi using the standard well-diffusion and micro-dilution methods. The following microorganisms were used: methicillin-resistant Staphylococcus aureus (ATCC 6538), muti-drug resistant Pseudomonas aeruginosa (ATCC 27853), enterohemorrhagic Escherichia coli (0157 EHEC), Salmonella typhi, Proteus vulgaris, Klebsiella pneumoniae, Bacillus subtilus (ATCC 6059, reference strain), Streptococcus pneumoniae, Klebsella pneumonia, MRSA, Corynebacterium, Corynebacterium diphtheriae and two fungus: Candida maltosa and Candida albicans . Results The different extracts possessed different inhibitory activity against different types of bacterial species. The patterns of inhibition varied with the plant extract, the solvent used for extraction and the organisms tested. The antimicrobial activity exhibited by the methanolic extracts of Boswellia sacra from the Suqotra and Dhofar regions was greater than that of Boswellia frereana collected from Somalia. The methanolic extract of the oleo-gum-resin showed higher efficacy to inhibit all the tested bacterial strains than the methanolic extract of frankincense-resin . The Boswellia frereana collected from Somalia showed lower activity compared with the two other Boswellia species. The plant extracts showed bacteriostatic activity at lower concentrations and bactericidal activity at higher concentrations. Neither water nor methanolic extracts showed any activity against the fungi Candida maltosa and Candida albicans . Conclusions It can be concluded that the methanolic extracts of Boswellia (Luban) possess the highest antibacterial activity. Neither water nor methanolic extracts show any activity against Candida maltosa and Candida albicans.

The past, current and future trends in DNA vaccine immunisations

This review focuses on DNA vaccines, denoting the last two decades since the early substantiation of preclinical protection was published in Science in 1993 by Ulmer et al. In spite of being safely administered and easily engineered and manufactured DNA vaccine, it holds the future prospects of immunization by inducing potent cellular immune responses against infectious and non-infectious diseases. It is well documented that injection of DNA plasmid encoding a desired gene of interest can result in the subsequent expression of its products and lead to the induction of an immune response within a host. This is pertinent to prophylactic and therapeutic vaccination approach when the peculiar gene produces a protective epitope from a pathogen. The recent studies demonstrated by a number of research centers showed that these immune responses evoke protective immunity against several infectious diseases and cancers, which provides adequate support for the use of this approach. We attempt in this review to provide an informative and unbiased overview of the general principles and concept of DNA vaccines technology with a summary of a novel approach to the DNA vaccine, present investigations that describe the mechanism(s) of protective immunity provoked by DNA immunization and to highlight the advantages and disadvantages of DNA immunisation.

Sero-prevalence of Helicobacter pylori infection among asymptomatic healthy Omani blood donors

Objective To investigate the prevalence of Helicobacter pylori (H. pylori) infection, a cross-sectional epidemiological study, based on the age and gender-specific seroprevalence of H. pylori antibodies in asymptomatic healthy Omani blood donors attending the SQUH blood bank.

Evaluation of anti-resistant activity of Auklandia (Saussurea lappa) root against some human pathogens.

OBJECTIVE The antimicrobial activity of the ethanol extract of the Auklandia (Saussurea lappa)root plant was investigated to verify its medicinal use in the treatment of microbial infections. METHODS The antimicrobial activity of the ethanol extract was tested against clinical isolates of some multidrug-resistant bacteria using the agar well diffusion method. Commercial antibiotics were used as positive reference standards to determine the sensitivity of the clinical isolates. RESULTS The extracts showed significant inhibitory activity against clinical isolates of methicillin resistant Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumonia, Extended Spectrum Beta-Lactemase, Acinetobacter baumannii. The minimum inhibitory concentration values obtained using the agar dilution test ranged from 2.0 µg/µL-12.0 µg/µL. In the contrary the water extract showed no activity at all against the tested isolates. Furthermore, the results obtained by examining anti-resistant activity of the plant ethanolic extract showed that at higher concentration of the plant extract (12 µg) all tested bacteria isolates were inhibited with variable inhibition zones similar to those obtained when we applied lower extract concentration using the well diffusion assay. CONCLUSION The results demonstrated that the crude ethanolic extract of the Auklandia (Saussurea lappa) root plant has a wide spectrum of activity suggesting that it may be useful in the treatment of infections caused by the above clinical isolates (human pathogens).

Occult hepatitis B virus among chronic liver disease patients in Yemen

Abstract Objective To estimate the rate of occult hepatitis B virus (HBV) among patients with chronic liver disease (CLD). Methods After an informed consent, sera samples were collected during April 2004 to April 2005 from 280 patients (200 male and 80 female). They were previously diagnosed with CLD based on history and ultrasound and were investigated for occult HBV infection. Sera were first screened for HBsAg and those which showed negative were tested for anti-HBc. The anti-HBc positive sera were further tested for anti-HBs to identify sera with isolated anti-HBc which in turn were subjected to HBV–DNA testing using PCR to determine the rate of occult HBV infection. Moreover, sera with occult HBV were tested for Anti-HCV and HCV-RNA using RT-PCR. Results HBsAg was detected in 44 of 280 (15.7%). Of 236 HBsAg negative sera anti-HBc was detected in 22 (9.3%). All anti-HBc positive sera were found to be anti-HBs negative. HBV–DNA was detected in 11 of 22 (50.0%) sera with isolated anti-HBc indicating occult HBV in 4.3% of all sera. None of the sera with occult HBV had anti-HCV or HCV-RNA. Conclusions Occult HBV infection does exist among CLD patients in Yemen and the mechanism of its occurrence merits further investigation.

Neutralisation of Local Haemorrhage Induced by the Saw-Scaled Viper Echis carinatus sochureki Venom Using Ethanolic Extract of Hibiscus aethiopicus L.

The objective of the study is to investigate the anti-snake venom activities of a local plant, Hibiscus aethiopicus L. The H. aethiopicus was dried and extracted with ethanol. Different assays were performed according to standard techniques, to evaluate the plants acute toxicity and its antivenom activities. The results of evaluating the systemic acute toxicity of the H. aethiopicus extract using “oral and intra-peritoneal” route were normal even at the highest dose (24 g/kg) tested. All guinea pigs (n = 3) when treated with venoms E. c. sochureki (75 μg) alone induced acute skin haemorrhage. In contrast, all guinea pigs (n = 18) treated with both venom and the plant extract at a concentration between 500 and 1000 mg/kg showed no signs of haemorrhage. Moreover, all guinea pigs (n = 18) treated with venom and the plant extract below 400 mg/kg showed acute skin haemorrhage. All guinea pigs treated with venom E. c. sochureki (75 μg) alone induced acute skin haemorrhage after both 24 and 32 hours. In contrast, all guinea pigs treated with both venom and the plant extract (administered independently) at concentrations between 500 and 1000 mg/kg showed no signs of haemorrhage after 32 hours. However, after 24 hours all tested guinea pigs showed less inhibition (<60%) compared to that obtained after 32 hours. The outcome of this study reflects that the extract of H. aethiopicus plant may contain an endogenous inhibitor of venom induced local haemorrhage.

In Vitro Apoptosis Triggering in the BT-474 Human Breast Cancer Cell Line by Lyophilised Camel's Milk.

Breast cancer is a global health concern and is a major cause of death among women. In Oman, it is the most common cancer in women, with an incidence rate of 15.6 per 100,000 Omani females. Various anticancer remedies have been discovered from natural products in the past and the search is continuing for additional examples. Cytotoxic natural compounds may have a major role in cancer therapy either in potentiating the effect of chemotherapy or reducing its harmful effects. Recently, a few studies have reported advantages of using crude camel milk in treating some forms of cancer. However, no adequate data are available on the lyophilised camels milk responsibility for triggering apoptosis and oxidative stress associated with human breast cancer. The present study aimed to address the role of the lyophilised camels milk in inducing proliferation repression of BT-474 and HEp-2 cells compared with the non-cancer HCC1937 BL cell line. Lyophilized camels milk fundamentally repressed BT-474 cells growth and proliferation through the initiation of either the intrinsic and extrinsic apoptotic pathways as indicated by both caspase-3 mRNA and its action level, and induction of death receptors in BT-474 but not the HEp-2 cell line. In addition, lyophilised camels milk enhanced the expression of oxidative stress markers, heme-oxygenase-1 and reactive oxygen species production in BT-474 cells. Increase in caspase-3 mRNA levels by the lyophilised camels milk was completely prevented by the actinomycin D, a transcriptional inhibitor. This suggests that lyophilized camels milk increased newly synthesized RNA. Interestingly,it significantly (p<0.003) repressed the growth of HEp-2 cells and BT-474 cells after treatment for 72 hours while 24 hours treatment repressed BT-474 cells alone. This finding suggests that the lyophilised camels milk might instigate apoptosis through initiation of an alternative apoptotic pathway.

New genetic variants in the CCR5 gene and the distribution of known polymorphisms in Omani population

C–C motif chemokine receptor‐5 (CCR5) is a pro‐inflammatory receptor that binds to chemokines and facilitates the entry of the R5 strain of HIV‐1. A number of polymorphisms were identified within the promoter and coding regions of the CCR5 gene, some of which have been found to affect the protein expression and thus receptor function. Although several CCR5 polymorphisms were shown to vary widely in their distribution among different ethnic populations, there has been no study addressing the potential variants of the CCR5 gene in the Omani population. The aim of this study was to identify the polymorphic sites that exist within the CCR5 gene in Omanis. Blood samples were collected from 89 Omani adult individuals, and genomic DNA was amplified by polymerase chain reaction and sequenced to identify the polymorphic sites. The distribution of the detected variants was examined and compared with the previously published data. Four new indels were detected of 32 variable positions, −2973A/–, −2894A/–, −2827TA/– and −2769T/–, and all were located in the 5′UTR. Furthermore, two new mutations, −2248G/A and +658A/G, were observed for the first time; the −2248G/A was detected in the intron 1 region in one subject and +658A/G in the coding region of the CCR5 in another subject. In silico analysis showed that the novel variations in the 5′UTR may have effects on the transcription factor binding sites. Therefore, this study demonstrates the presence of two new SNPs and four novel indels in the CCR5 gene in the Omani population. Our findings support the wide spectrum of genetic diversity reported within the CCR5 gene region among different ethnic groups.