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Dive into the research topics where Tawfeq A. Al-Howiriny is active.

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Featured researches published by Tawfeq A. Al-Howiriny.


Journal of Ethnopharmacology | 2003

Antihepatotoxic activity of seeds of Cichorium intybus

Bahar Ahmed; Tawfeq A. Al-Howiriny; Abu B. Siddiqui

The different fractions of alcoholic extract and one phenolic compound AB-IV of seeds of Cichorium intybus Linn were screened for antihepatotoxic activity on carbon tetrachloride (CCl(4))-induced liver damage in albino rats. The degree of protection was measured using biochemical parameters like aspartate transaminase (AST), alanine transaminase (ALT), alkaline phosphatase (ALKP), and total protein (TP). The methanol fraction and compound AB-IV were found to possess a potent antihepatotoxic activity comparable to the standard drug Silymarin (Silybon-70). The histopathological study of the liver was also carried out, wherein the methanolic fraction and compound AB-IV showed almost complete normalization of the tissues as neither fatty accumulation nor necrosis was observed.


Natural Product Research | 2007

Phytochemical and biological studies on Saudi Commiphora opobalsamum L.

Fawkeya A. Abbas; Shaza M. Al-massarany; Shabana I. Khan; Tawfeq A. Al-Howiriny; Jaber S. Mossa; Ehab A. Abourashed

The aerial part of Commiphora opobalsamum L. (Burseraceae) growing in Saudi Arabia was subjected to a phytopharmacological investigation in order to identify its major chemical constituents and to evaluate its extracts and isolated compounds in preliminary in vitro assays for antimicrobial, antimalarial, antitumor, anti-inflammatory (COX-2 inhibition), antioxidant and estrogenic activity. Six compounds were isolated and identified as the triterpenes friedelin, canophyllal, and oleanonic acid; the flavonols mearnsetin and quercetin; and syringic acid. The ethyl acetate extract was moderately active against Staphylococcus aureus, Pseudomonas aeruginosa, and Plasmodium falciparum; while the petroleum ether and chloroform extracts inhibited COX-2 at 5 and 10 µg mL−1, respectively. Of the isolated compounds, syringic acid showed moderate antimalarial, anticandidal, and antimycobacterial activity; while mearnsetin and quercetin exhibited antioxidant activity comparable to ascorbic acid and trolox. This is the first detailed phytochemical investigation of C. opobalsamum L. growing in Saudi Arabia and elsewhere. The isolated compounds are reported from this plant for the first time and their full 1H and 13C NMR assignments are included.


The American Journal of Chinese Medicine | 2003

Prevention of Experimentally-induced Gastric Ulcers in Rats by an Ethanolic Extract of "Parsley" Petroselinum crispum

Tawfeq A. Al-Howiriny; Mohammed Al-Sohaibani; Kamal Eldin H. ElTahir; Syed Rafatullah

An ethanolic extract of Parsley, Petroselinum crispum (Mill.) Nym.ex A.W. Hill (Umbelliferae), was tested for its ability to inhibit gastric secretion and to protect gastric mucosa against the injuries caused by pyloric ligation, hypothermic restraint stress, indomethacin and cytodestructive agents (80% ethanol, 0.2 M NaOH and 25% NaCl) in rats. The extract in doses of 1 and 2 g/kg body weight had a significant antiulcerogenic activity on the models used. Besides, ethanol-induced depleted gastric wall mucus and non-protein sulfhydryl contents were replenished by pretreatment with Parsley extract. Acute toxicity tests showed a large margin of safety for the extract. The phytochemical screening of Parsley leaves revealed the presence of tannins, flavonoids, sterols and/or triterpenes.


Pharmaceutical Biology | 2010

Gastric antiulcer, antisecretory and cytoprotective properties of celery (Apium graveolens) in rats

Tawfeq A. Al-Howiriny; Abdulmalik Alsheikh; Saleh I. Alqasoumi; Mohammed A. Al-Yahya; Kamal Eldin H. ElTahir; Syed Rafatullah

In the present investigation, an ethanol extract of celery [Apium graveolens L. (Apiaceae/Umbelliferae)], at doses of 250 and 500 mg/kg body weight, was evaluated for antigastric ulcer activity using various experimental gastric ulcer models in rats. Ulcers were induced by indomethacin, cytodestructive agents (80% ethanol, 0.2 M NaOH and 25% NaCl) and cold restraint stress. Gastric secretory studies were undertaken by using pylorus ligation (Shay rat model). In addition to gastric wall mucus (GWM), non-protein sulfhydryl (NP-SH) and malondialdehyde (MDA) were also estimated in gastric tissues after 80% ethanol treatment. Pretreatment of celery extract produced dose-dependent reduction in all experimentally induced gastric lesions. Ethanol (80%) decreased the levels of GWM, NP-SH and increase in MDA concentration in gastric tissue. Celery extract showed the ability to significantly replenish the ethanol-induced depleted levels of GWM and gastric mucosal NP-SH. The gastric mucosal MDA level was also significantly lowered in extract pretreated rats. The celery extract showed stomach protection against the models used for ulcerogenesis. Results were further confirmed by using histopathological assessment. The phytochemical screening showed the presence of various chemical constituents such as flavonoids, tannins, volatile oils, alkaloids, sterols and/or triterpenes. Acute toxicity test revealed no deleterious or toxic symptoms or mortality over a period of 14 days. However, the LD50 was found to be 7.55 g/kg, and showed a large margin of safety. The results suggest that Apium graveolens extract significantly protects the gastric mucosa and suppresses the basal gastric secretion in rats, possibly through its antioxidant potential.


Natural Product Research | 2005

Three new diterpenes and the biological activity of different extracts of Jasonia montana

Tawfeq A. Al-Howiriny; Adnan J. Al-Rehaily; Joanna R. Pols; John R. Porter; Jaber S. Mossa; Bahar Ahmed

Three new diterpenes, namely jasonin-a (1), jasonin-b (2), and jasonin-c (3) were isolated from the aerial parts of Jasonia montana (Asteraceae). Their structures were elucidated on the basis of spectral data as [(1E)-2-((2S)-1,2,5-trimethylbicyclo[3.2.1]octan-8-yl)vinyl] benzene-3-carboxylic acid (1), [3-((2S, 5S)-1,2, 5-trimethylcycloheptanyl)propyl]benzene-3-carboxylic acid (2), and [(1E)-3-((7R)-1,7-dimethy-4-methylenecycloheptanyl)prop-1-enyl] benzene-3-carboxylic acid (3). In addition, the previously reported 5,7,3′-trihydroxy-3,6,4′-trimethoxy flavone designated as centaureidin (4), was also isolated and characterized from this source. The different extracts of the plant were also screened for hypoglycemic, antidiabetic, and antimicrobial activities, wherein the petroleum ether and ethanolic extracts exhibited hypoglycemic and antidiabetic activity, and the petroleum ether and chloroform extracts showed antimicrobial activity.


Phytochemistry | 2012

Acylated pregnane glycosides from Caralluma sinaica.

Samuel Bertrand; Andreas Nievergelt; Azza Muhammed El-Shafae; Tawfeq A. Al-Howiriny; Nawal M. Al-Musayeib; Muriel Cuendet; Jean-Luc Wolfender

Caralluma sinaica is sold on local markets of Saudi Arabia for various health benefits however no phytochemical study has specifically been performed on this species. NMR and UHPLC-ESI-TOF-MS profilings of the ethanolic extract of the whole plant reveal a very complex phytochemical composition dominated by pregnanes. Detailed information on its constituents was obtained after isolation. Six pregnane glycosides were obtained and characterized based on the extensive spectroscopic analysis (including IR, ¹H NMR, ¹³C NMR and MS data), in addition to ten known compounds (seven pregnanes and three flavonoids). The compounds were identified as 12β-O-benzoyl-20-O-acetyl boucerin-3-O-6-deoxy-3-O-methyl-β-D-glucopyranosyl-(1-->4)-β-D-cymaropyranosyl-(1-->4)-β-D-cymaropyranoside, 12β-O-tigloyl-20-O-acetyl boucerin-3-O-β-D-glucopyranosyl-(1-->4)-β-D-cymaropyranoside, 12β-O-benzoyl-20-O-acetyl boucerin-3-O-β-D-glucopyranosyl-(1-->4)-β-D-digitalopyranosyl-(1-->4)-β-D-cymaropyranosyl-(1-->4)-β-D-cymaropyranoside, 12β-O-benzoyl-20-O-acetyl boucerin-3-O-β-D-glucopyranosyl-(1-->4)-hevetopyranosyl-(1-->4)-β-D-cymaropyranosyl-(1-->4)-β-D-cymaropyranoside, 12β-O-benzoyl-20-O-tigloyl boucerin-3-O-β-D-glucopyranosyl-(1-->4)-β-D-cymaropyranoside, 12β-20-O-dibenzoyl boucerin-3-O-β-D-glucopyranosyl-(1-->4)-β-D-cymaropyranosyl-(1-->4)-β-D-cymaropyranoside. Finally, the isolated compounds were evaluated for their quinone reductase induction.


Phytochemistry | 2001

Alkaloids from Haplophyllum tuberculatum.

Adnan J. Al-Rehaily; Tawfeq A. Al-Howiriny; Mohammad Ahmad; Mohammad A. Al-Yahya; Farouk S. El-Feraly; Charles D. Hufford; Andrew T. McPhail

Two new alkaloids, haplotubinone (3) and haplotubine (4), were isolated from the aerial parts of Haplophyllum tuberculatum together with the known lignan diphyllin. The structures of the new alkaloids were established by spectroscopic methods in conjunction with X-ray crystallographic analysis of 3. In addition, the amide N-(2-phenylethyl)-benzamide has been identified in this source for the first time.


Biofactors | 2010

Ginger ingredients inhibit the development of diethylnitrosoamine induced premalignant phenotype in rat chemical hepatocarcinogenesis model

Mahmoud A. Mansour; Saleh A. Bekheet; Salim S. Al-Rejaie; Othman A. Al-Shabanah; Tawfeq A. Al-Howiriny; Ammar C. Al-Rikabi; Ayman A. Abdo

To investigate the possible antitumor activity of ginger extract against hepatic carcinogenesis initiated by diethylnitrosoamines (DEN) and promoted by carbon tetrachloride (CCl4). A total of 60 male Wistar albino rats were divided into four groups with 15 animals in each group. Rats in group 1 (control group) received a single intraperitoneal (i.p.) injection of normal saline. Animals in group 2 were given ginger (50 mg/kg/day) in drinking water for 8 weeks. Rats in group 3 (DEN group) were injected with a single dose of DEN (200 mg/kg, i.p.), 2 weeks later received a single dose of CCl4 (2 mL/kg i.g) by gavage as 1:1 dilution in corn oil. Animals in group 4 (DEN‐ginger group) received the same carcinogenesis induction protocol as in group 3 plus ginger (50 mg/kg/day) in drinking water for 2 weeks before induction of hepatocarcinogenesis and continued throughout the experimental period. DEN‐initiated and CCl4‐promoted hepatocarcinogenesis in male Wistar rats was manifested biochemically by elevation of serum hepatic tumor markers tested; α‐fetoprotein and carcinoembryonic antigen. In addition, hepatocarcinogenesis was further confirmed by a significant increase in hepatic tissue growth factors; vascular endothelial growth factor, basic fibroblast growth factor, and hydroxyproline content. A marked decrease in endostatin and metallothonein were also observed. Long‐term ginger extract administration 2 weeks before induction of hepatocarcinogenesis and throughout the experimental period prevented the decrease of the hepatic content of metallothionein and endostatin and the increase in the growth factors induced by the carcinogen. Moreover, ginger extract normalize serum hepatic tumor markers. Histopathological examination of liver tissue also correlated with the biochemical observations. These findings suggest a protective effect of ginger extract against premalignant stages of liver cancer in the DEN‐initiated and CCl4‐promoted hepatocarcinogenesis model in rats.


Zeitschrift für Naturforschung C | 2004

Verbenacine and Salvinine: Two New Diterpenes from Salvia verbenaca

Bahar Ahmed; Tawfeq A. Al-Howiriny; Adnan J. Al-Rehaily; Jaber S. Mossa

Two new diterpenes namely verbenacine (1) and salvinine (2) have been isolated from the aerial parts of Salvia verbenaca. Their structures have been elucidated on the basis of chemical and spectral data as 3α-hydroxy-19-carboxykaur-15-ene and 19-hydroxy-12,14-dioxo labda-15,17-diene.


Journal of Essential Oil Research | 2003

Essential Oil of Rosa abyssinica R. Br. from Saudi Arabia

Adnan J. Al-Rehaily; Tawfeq A. Al-Howiriny; Humberto R. Bizzo

Abstract The essential oil of the aerial parts (including flowers) of Rosa abyssinica R. Br. was investigated by GC and GC/MS. Thirty-five components were identified in the oil, representing 93.3%. The main components were γ-muurolene (13.0%) and caryophyllene oxide (26.6%).

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