Phytochemical and Biological Studies of Medicinal Plants in Bahrain: The Family Chenopodiaceae—Part 2

Al-Saleh, Fawzia; El-Din, Alaa; Abbas, J. A.; Saeed, Naima

doi:10.1076/phbi.35.1.38.13266

Cited by 25 publications

(20 citation statements)

References 6 publications

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“…For example, Dawes-Gromadzki (2002) investigated the thermodynamic bottom-up model for arthropods of a chenopod shrubland community and found only weak direct effects of enhanced nutrients on herbivores and no effects on upper trophic levels. Plants in the Chenopodiaceae are rich sources of both carbon-based (e.g., flavonoids, terpenoids, and steroids) and nitrogenbased (alkaloids) defenses (Aljaber et al 1992, Alsaleh et al 1997. Thus, the failure to find classic bottomup effects in the chenopod system could be due to the fact that resource availability increased plant quantity but decreased quality.…”

Section: Discussionmentioning

confidence: 99%

Ecological Causes and Consequences of Variation in Defensive Chemistry of a Neotropical Shrub

Dyer

Letourneau

Dodson

et al. 2004

Ecology

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Prominent models of herbivore regulation focus on predators, low plant biomass, or poor resource quality as factors that limit herbivore populations. We examined predictions of these tritrophic models for herbivores on the understory shrub, Piper cenocladum, which is defended by mutualistic ants (Pheidole bicornis) and three amide secondary metabolites. To examine sources of variation in P. cenocladum amide content and to compare the effects of amides vs. ants on herbivores, we used three linked experiments in the field and in shadehouses. We manipulated light, nutrient availability, and presence of symbionts for experimental plant fragments and shrubs and then quantified leaf amide concentration. We also examined relationships between amide content and damage by the three most common groups of folivores on P. cenocladum: generalist orthopterans, specialist coleopterans, and specialist lepidopterans. For all experiments, enhanced resources and absence of symbionts caused higher levels of amides. These increased chemical defenses had strong effects on generalist herbivores in this system, while the ant predators were more effective at depressing herbivory by specialists. The negative effects of amides on specialist lepidopterans were small, suggesting that these herbivores are adapted to chemical defenses in their host plant. It is possible that our results are part of a more general trend where top-down effects are stronger against specialist herbivores, while chemical defenses are more effective against generalists. We concluded that different models of herbivore regulation were supported by components of the P. cenocladum arthropod community, depending on resource availability and on the portion of the web examined.

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Section: Discussionmentioning

confidence: 99%

Ecological Causes and Consequences of Variation in Defensive Chemistry of a Neotropical Shrub

Dyer

Letourneau

Dodson

et al. 2004

Ecology

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“…Flavonoidrich plant extracts from species of Hypericum [54], Capsella [55] and Chromolaena [55] have been reported to possess antibacterial activity. Many other phytochemical preparations with high flavonoid content have also been reported to exhibit antibacterial activity [22,[56][57][58][59][60][61][62][63]. Propolis has been analysed on many occasions too, and samples containing high concentrations of flavonoids are frequently reported to show antibacterial activity [12,[25][26][27]50,64].…”

Section: Reports Of Flavonoids Possessing Antibacterial Activitymentioning

confidence: 99%

“…From the published work it is clear that, in addition to inoculum size, there are many other variable factors for each type of assay. These include volume of broth or agar [90,116], type of broth or agar [86,92], size of wells [56,60], size of paper disks [57,65], strains of a particular bacterial species used [69,72] and incubation period [90,116].…”

Section: Discrepancies Between Reports Of Flavonoid Antibacterial Actmentioning

confidence: 99%

Antimicrobial activity of flavonoids

Cushnie

Lamb

2005

International Journal of Antimicrobial Agents

3,404

1,980

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Flavonoids are ubiquitous in photosynthesising cells and are commonly found in fruit, vegetables, nuts, seeds, stems, flowers, tea, wine, propolis and honey. For centuries, preparations containing these compounds as the principal physiologically active constituents have been used to treat human diseases. Increasingly, this class of natural products is becoming the subject of anti-infective research, and many groups have isolated and identified the structures of flavonoids possessing antifungal, antiviral and antibacterial activity. Moreover, several groups have demonstrated synergy between active flavonoids as well as between flavonoids and existing chemotherapeutics. Reports of activity in the field of antibacterial flavonoid research are widely conflicting, probably owing to inter- and intra-assay variation in susceptibility testing. However, several high-quality investigations have examined the relationship between flavonoid structure and antibacterial activity and these are in close agreement. In addition, numerous research groups have sought to elucidate the antibacterial mechanisms of action of selected flavonoids. The activity of quercetin, for example, has been at least partially attributed to inhibition of DNA gyrase. It has also been proposed that sophoraflavone G and (-)-epigallocatechin gallate inhibit cytoplasmic membrane function, and that licochalcones A and C inhibit energy metabolism. Other flavonoids whose mechanisms of action have been investigated include robinetin, myricetin, apigenin, rutin, galangin, 2,4,2'-trihydroxy-5'-methylchalcone and lonchocarpol A. These compounds represent novel leads, and future studies may allow the development of a pharmacologically acceptable antimicrobial agent or class of agents.

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“…Herbal medicine is still widely practiced as therapeutical agents for various diseases in the Arab region including the Gulf states. Previous reports of works conducted at our institution included the study of various aspects of medicinal plants of Bahrain El-Oqlah and Abbas, 1994;Al-Saleh et al, 1997;Abbas and Al-Saleh, 2002;Alkhuzai et al, 2010a,b). More recently, the potential of some medicinal plants of Bahrain as natural sources of important essential fatty acids has been explored (Freije et al, 2013).…”

Section: Introductionmentioning

confidence: 95%

Assessment of antioxidant activities of three wild medicinal plants from Bahrain

Allaith

Alkhuzai

Freije

2019

Arabian Journal of Chemistry

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This study reports the antioxidant properties of three wild medicinal plants from Bahrain, namely Aizoon canariense L., Asphodelus tenuifolius Cav., and Emex spinosus (L.) Campdera. Antioxidant and antiradical activities of dried materials of these plants were investigated using FRAP, DPPH and ABTS assays. Total phenolics, free phenolics and total flavonoids were also determined. E. spinosus was ranked by the assays as the plant possessing the highest antioxidant and antiradical activities with an average FRAP value of 1.84 mmol/g and IC 50 of 10.7 and 7.75 mg/ml for DPPH and ABTS assays, respectively. A. tenuifolius ranked second with a mean FRAP value of 0.69, IC 50 DPPH of 1.72 and ABTS of 0.36. A. canariense possessed the lowest activities with a mean FRAP value of 0.6, and averaged IC 50 of 103.8 and ABTS of 14.6. E. spinosus possessed the highest content of free phenolics (mg/100 g) (64.64) followed by A. tenuifolius (45.21) and A. canariense (32.23). E. spinosus also exhibited the highest total flavonoids with an average 82.71 mg/100 g followed by A. canariense (55.92) and A. tenuifolius (49.10). The studied medicinal plants possess considerable antioxidant activities and may contribute to the well-being of individuals who consume them. ª 2015 The Authors. Production and hosting by Elsevier B.V. on behalf of King Saud University. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

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Phytochemical and Biological Studies of Medicinal Plants in Bahrain: The Family Chenopodiaceae—Part 2

Cited by 25 publications

References 6 publications

Ecological Causes and Consequences of Variation in Defensive Chemistry of a Neotropical Shrub

Ecological Causes and Consequences of Variation in Defensive Chemistry of a Neotropical Shrub

Antimicrobial activity of flavonoids

Assessment of antioxidant activities of three wild medicinal plants from Bahrain

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