Phenolic compounds and polysaccharides in the date fruit (Phoenix dactylifera L.): Comparative study on five widely consumed Arabian varieties.

The study analysed polysaccharides and phenolic compounds in widely consumed but little studied date fruits varieties such as Sukkari, Ajwa, Segae, Barrny and Khalas harvested at Tamr stage. The total phenols were in similar amount in the five varieties and ranged from 20 to 50 mg/100 g DW. The decoction and successive centrifugation made it possible to collect two main polysaccharide fractions for all the selected fruits. For each variety the first fraction was more abundant, with a lower swelling capacity and a higher amount of galacturonic acid (28.3% to 40.1%). The second fraction was only soluble in alkaline solution, with an average galacturonic acid content of only 17%. The different structure of the two polysaccharide fractions was also confirmed by the composition in neutral sugars and the degrees of methylation and acetylation. The proposed extraction procedure could be applied for larger scale extraction of the date fruit polysaccharides.

Antimicrobial and anti-biofilm activities of polyphenols extracted from different Saudi Arabian date cultivars against human pathogens.

BACKGROUND: Microbial diseases have emerged as a serious threat to the healthcare system globally and also in Saudi Arabia; various diseases are associated with higher mortality and increased spreading rates. Dietary sources are often entertained to improve the immune system of the body to fight against these infections. The date fruit (Phoenix dactylifera L) is one such functional food that is less explored for its actual potentials. METHODS: The polyphenols isolated from the different cultivars of dates in Saudi Arabia (Ajwa, Safawi, Khalas, and Sukkary) was evaluated for their antibacterial, anti-fungal and anti-biofilm forming abilities. The anti-radical properties of the phenolic extract were conducted in terms of the scavenging of diphenyl-1-picrylhydrazyl radical, hydrogen peroxide radicals and ABTS radicals. The anti-inflammatory potential was analyzed in terms of lipoxygenase activity inhibition. RESULTS: The phenolic compounds of different dates were spectrophotometrically estimated and cultivars such as Ajwa and Sukkary had the highest polyphenol content. It was also noteworthy that they exerted potent antibacterial activities against Staphylococcus aureus, Streptococcus pyogenes, and Pseudomonas aeruginosa as estimated by the least minimal inhibitory concentration (MIC) or minimal bactericidal concentration (MBC) values. Besides, these polyphenols reduced the biofilm formation by these bacterial pathogens; it is thus possible that the polyphenols from dates can be a promising antimicrobial agent against various pathogenic strains. Corroborating with these, the polyphenol extracts from different Saudi Arabian dates were found to inhibit the growth of mycelium in strains of Candida albicans and Aspergillus niger. Apart from these, the polyphenol isolates also exhibited significant anti-radical properties against different reactive radical systems. CONCLUSION: Overall, the efficacy of phenolic compounds extracted from the dried date fruits are not only restricted to the functional food features; instead, these molecules are capable of preventing the growth of microbial pathogens of humans. Hence, it may emerge as potent antibacterial, anti-fungal and anti-biofilm forming candidates.

Emerging paradigms of viral diseases and paramount role of natural resources as antiviral agents.

In the current scenario, the increasing prevalence of diverse microbial infections as well as emergence and re-emergence of viral epidemics with high morbidity and mortality rates are major public health threat. Despite the persistent production of antiviral drugs and vaccines in the global market, viruses still remain as one of the leading causes of deadly human diseases. Effective control of viral diseases, particularly Zika virus disease, Nipah virus disease, Severe acute respiratory syndrome, Coronavirus disease, Herpes simplex virus infection, Acquired immunodeficiency syndrome, and Ebola virus disease remain promising goal amidst the mutating viral strains. Current trends in the development of antiviral drugs focus solely on testing novel drugs or repurposing drugs against potential targets of the viruses. Compared to synthetic drugs, medicines from natural resources offer less side-effect to humans and are often cost-effective in the productivity approaches. This review intends not only to emphasize on the major viral disease outbreaks in the past few decades and but also explores the potentialities of natural substances as antiviral traits to combat viral pathogens. Here, we spotlighted a comprehensive overview of antiviral components present in varied natural sources, including plants, fungi, and microorganisms in order to identify potent antiviral agents for developing alternative therapy in future.

Analysis of the cuticular wax composition and ecophysiological studies in an arid plant - Ziziphus nummularia (Burm.f.) Wight & Arn.

Plants in arid regions are exposed to various abiotic stresses and the presence of the waxy cuticular layer acts as a defensive barrier, which consists mainly of long chain fatty acids, hydrocarbons and other derived compounds. Studies on the chemical composition and properties of cuticles of arid plants are scanty. The present study deals with the analysis of cuticular wax composition and effect of temperature on some ecophysiological parameters of an important arid plant Ziziphus nummularia. A total of 59 different wax compounds were detected from the leaf cuticle by capillary GC-MS. 4-Hydroxycyclohexanone, Heptacosane and 2,7-Dimethyloctane-3,5-dione were the dominant wax compounds in Z. nummularia. The variation of photosynthetic rate varied from 0.70 to 7.70 µmol CO2 m-2s-1 against the studied temperature range of 15-55 °C. The transpiration rate varies from 1.80 to 8.40 mmol H2O m-2s-1 within the temperature range of 15-55 °C. The quantum yield of photosystem II (Fv/Fm) also exhibited much variation due to the variation of temperature. The results clearly shows that Z. nummularia is highly adapted to restrict water loss and can tolerate high temperatures and can be considered as an appropriate species for vegetating the arid areas.

Quaternary ammonium compounds in roots and leaves of Capparis spinosa L. from Saudi Arabia and Italy: investigation by HPLC-MS and 1H NMR.

Capparis spinosa L. is a perennial plant typical of the Mediterranean flora and a multipurpose plant used for curing various human ailments. Quaternary ammonium compounds (QACs), as constituents of Capparaceae, play important roles in protecting against abiotic stress. Aim of this work was to determine QACs in root and leaves of caper from two proveniences. The presence of stachydrine, choline, glycine betaine and homo-stachydrine has been confirmed by high resolution MS, while 1H NMR was applied to quantify the main QACs in the aqueous extracts. Stachydrine was quantified at 20.2 mg/g and 32.3 mg/g on dry leaves from South of Italy and Saudi Arabia, respectively, while a minor content was in dry roots (from 10.4 to 12.5 mg/g). Choline was considerably lower both in leaves and roots (from 0.3 to 1.2 mg/g). To our knowledge, this is the first report on the determination of QACs both in root and leaves of C. spinosa.

Polysaccharides from by-products of the Wonderful and Laffan pomegranate varieties: New insight into extraction and characterization.

The main crude polysaccharides (CPS), extracted from two widely cultivated pomegranate varieties, Laffan and Wonderful, were studied and characterized. We obtained the highest CPS extraction yield (approximatively 10% w/w on dried matter) by 1h of decoction (ratio 1/40w/v). The predominant polymers (75-80%) of the CPS samples showed a hydrodynamic volume close to 2000kDa by size exclusion chromatography and the exocarp and mesocarp profiles were very similar. The proton spectra (1H NMR), according to sugar composition and gelling ability, confirmed the main polysaccharide fractions were pectin with different acylation and methylation degree. The CPS from Laffan and Wonderful mesocarp showed prebiotic properties in vitro with Lactobacillus and Bifidobacterium strains. The composition of the decoction (12% ellagitannins and 10% of CPS) obtained by a green extraction process of pomegranate by-products, makes it a suitable component of functional food formulations.