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The lack of treatment options for COVID-19 has raised many concerns among populations worldwide, which has led to many attempts to find alternative options to prevent the transmission of the disease or to alleviate the progression of the infection, including focusing more on preventive measures (to prevent transmission to other individuals) and the use of natural products and herbal extracts to increase immunity and decrease the probability of getting infected. This study explored the knowledge of the population of the Kingdom of Saudi Arabia (KSA) about COVID-19 preventive measures and their belief about the consumption of herbal products for the prevention of COVID-19 infection. A total of 5,258 individuals participated in this study. Participants' knowledge about the appropriate COVID-19 preventive measures in terms of handwashing procedures, self-quarantine and social distancing was moderate, with a mean score of 5.5 (SD: 1.7) out of 10 (representing around 55.0% of the total score). About 22.1% (n = 1,161) of the participants reported that they have used herbal products or nutritional supplements during the pandemic period, to protect themselves from the disease. Social media and the Internet (39.4%, n = 372) were the main motivators for the participants to try herbal products. Vitamin C was the most commonly used food supplement to increase immunity and reduces the chance of contracting COVID-19. Our study demonstrated that the general population in Saudi Arabia has a moderate level of knowledge about COVID-19 transmission and preventive measures. A considerable proportion of the population reported the use of herbal products or food supplements in order to protect themselves from the disease. Policymakers are suggested to provide further educational campaigns that increase population knowledge about the disease transmission routes and preventive measures. In addition, the use of herbal products should be evidence-based to ensure patient safety. [ABSTRACT FROM AUTHOR]

• The Agavaceae species extracts had promising cytotoxicity against some cancer cells. • Some fractions from P. tuberosa, Y. filamentosa and F. Watsoniana had strong cytotoxicity. • Cytotoxicity shown by extracts may be related to steroidal saponins present. Among the plants which are determined to be a promising source of anticarcenogenic agents are members of Agavaceae family which are common in tropical and subtropical regions such as Egypt. In this study, cytotoxic activity were assessed for the methanolic extracts and fractions from five members of Agavaceae family: Sansevieria cylindrica Bojer., Polianthes tuberosa L., Sansevieria trifasciata Prain., Yucca filamentosa L. and Furcraea watsoniana Hort. against MCF-7 (breast), HepG-2 (hepatoma), and Caco-2 (colon) cancer cell lines by MTT method. The n -hexane fraction of P. tuberosa leaves extract demonstrated strong cytotoxic potential against all three cancer cell lines (CC 50 <20 µg/ml). The ethyl acetate fractions of Y. filamentosa and F. watsoniana leaves significantly inhibited proliferation of hepatocellular HepG-2 (CC 50 = 6.21 µg/ml and 19.07 µg/ml, respectively) and intestinal epithelium Caco-2 carcinoma cells (CC 50 = 18.86 µg/ml and 23.25 µg/ml, respectively). Presumably, the cytotoxic activity exhibited by n -hexane fraction of P. tuberosa , ethyl acetate fractions of Y. filamentosa and F. watsoniana may be related to the steroidal saponins that are present in these samples. [ABSTRACT FROM AUTHOR]

This paper presents a detailed study of Photovoltaic (PV) system performance under desert environmental effects in order to maximize the captured energy of PV system. The proposed study mainly focused on the output power loss of the PV system due to dust accumulation to determine the optimum tilt angle. Eight PV panels were installed on the roof of Faculty of Engineering, Upper Egypt-located in desert environment, at 15°, 20°, 30° and 45° tilt angles with the intention to analyze and compare the performance of the cleaned and dusty solar panels. The output power is recorded for cleaned and dusty solar panels with different tilt angles through the test period. Also, the effect of the panel surface temperature is experimentally studied. The measured data shows that the dust accumulation on the surface of the solar panels reduces the output power. The reduction ratio depends on the number of uncleaned days and tilt angle. The reductions in the output power for dusty panels after ten months of dust accumulation are 43%, 38%, 31%, and 25.5% for tilt angles of 15°, 20°, 30° and 45°, respectively. Also, the optimum tilt angle that gives maximum average output power depends on number of uncleaned days for the dusty panels. On the other hand, the optimum tilt angle for cleaned panels is mainly depends on the season variations. An empirical formula for the output power reduction of the solar panel is proposed and validated to illustrate the correlation between the numbers of dust accumulation days and tilt angle. It helps solar panel system designers to accurately predict the amount of solar power reduction and optimum tilt angle for a specified cleaning schedule. [ABSTRACT FROM AUTHOR]

An ellagitannin monomer, lythracin M (1), and a dimer, lythracin D (2), along with eight known monomers (3 − 10) were isolated from Lawsonia inermis (Lythraceae) leaves. Lythracin M (1) is a C -glycosidic ellagitannin with a flavogallonyl dilactone moiety that participates in the creation of a γ-lactone ring with the anomeric carbon of the glucose core. Lythracin D (2) was determined as an atropisomer of the reported lythcarin D. These newly discovered structures (1 and 2) were determined by intensive spectroscopic experiments and by comparing DFT-calculated 1H 1H coupling, 1H NMR chemical shifts, and ECD data with experimental values. The anti-acetylcholinesterase assay of the compounds 1 – 10 revealed that the C-1 ellagitannin epimers [casuarinin (7 ; IC 50 = 34 ± 2 nM) and stachyurin (8 ; IC 50 = 56 ± 3 nM)], and the new dimer (2 ; IC 50 = 61 ± 4 nM) possess enzyme inhibitory effects comparable to the reference drug (donepezil, IC 50 = 44 ± 3 nM). Molecular docking of compounds 1 – 10 with AChE identified the free galloyl moiety as an important pharmacophore in the anticholinesterase activity of tannins. [Display omitted] • Two new (1 and 2) and eight known ellagitannins (3 – 10) were isolated from leaves of L. inermis. • The stereo-structure of 1 was established based on DFT calculations and intensive spectroscopic studies. • The anti-AChE activity of 1 – 10 was evaluated experimentally and by using molecular docking. • The ellagitannins 2 , 7 , and 8 are promising anti-AChE. [ABSTRACT FROM AUTHOR]

Re-investigation of the culture broth of the marine bacterium Staphylococcus sp. (no. P-100826-4-6) afforded a new cyclic tetrapeptide namely staphylopeptide A ( 1 ), along with five known compounds, cyclo ( l -prolyl- l -valine) ( 2 ), cyclo ( l -prolyl- l -tyrosine), ( 3 ), cyclo ( l -prolyl- l -alanine) ( 4 ), l -phenylalanine ( 5 ), and l -tryptophan ( 6 ). The structures of the isolated compounds were determined by extensive IR, 1D ( 1 H and 13 C) and 2D ( 1 H- 1 H COSY, HSQC, HMBC, and NOESY) NMR and HRFABMS spectral measurements. The antimicrobial activity of the isolated compounds ( 1–6 ) was evaluated. [ABSTRACT FROM AUTHOR]

Chromatographic separation of an aqueous acetone extract of the galls from Tamarix aphylla using gels resulted in isolation of an ellagitannin, phyllagallin M1 ( 13 ), a gallo-ellagitannin, phyllagallin D1 ( 14 ), and four gallotannins, phyllagallin M2 ( 15 ) and phyllagallins D2–D4 ( 16 – 18 ), in addition to four known ellagitannins and three phenolics of lower molecular weight structurally related to hydrolyzable tannins. The structures of the six new tannins were elucidated based on spectroscopic and chemical data. Among the phenolics, flavogallonic acid dilactone ( 8 ), which is presumed to be biogenetically produced by C–C oxidative coupling of an ellagic acid unit with a galloyl residue, shows an exceptional oxidative pattern of gallic acid residues in plants of the family Tamaricaceae. Although the ellagitannin tamarixellagic acid ( 4 ) was reported to be a constituent of the galls of T. aphylla , such compounds with anomalous location of the DHDG moiety at O-3 on the glucopyranose core have not been observed among the tannins of tamaricaceous plants. [ABSTRACT FROM AUTHOR]

An on chip integrated power management circuit with maximum power point tracking (PM-MPPT) control is proposed in this paper in order to achieve high efficiency Photovoltaic (PV) system. The proposed PM-MMPT circuit mitigates partial shading issues which exist in PV systems by utilizing cell-level distributed MPPT architecture, where each cell has its own MPPT circuit, in order for each cell to produce its own maximum power without affecting other cells or being affected by other cells. The proposed PM-MPPT circuit consists of two different parts. The first part is a high-efficiency synchronous power converter stage. The second part is an analog ripple correlation control (RCC) MPPT control circuit which provides faster and efficient MPP tracking, has less circuit complexity and low power consumption. HSPICE simulation model of the proposed PM-MPPT circuit is developed with a solar cell that has 0.5 V open circuit voltage and 6 A short circuit current. Simulation results show that the proposed PM-MPPT circuit rapidly tracks the MPP with a tracking efficiency larger than 99% over a wide range of irradiation levels and 92% system power conversion efficiency at a 2 W power level. The detailed analog design of the power stage and the RCC MPPT circuits are presented and discussed in the paper based on 0.35 μm CMOS technology. In addition, the PM-MMPT IC layout is presented and discussed. To validate the proposed technique and design, a comparison between the results of the proposed circuit and other reported techniques from the literature is provided. It is shown that the proposed circuit and system are able to operate with the lowest input voltage and the highest output power compared with other reported techniques. Moreover, the proposed design has the smallest size under 2 W power level. [ABSTRACT FROM AUTHOR]

Abstract: Shoot cultures of Tamarix tetrandra on Linsmaier–Skoog (LS) agar medium with 30gl−1 sucrose, 2.13mgl−1 indoleacetic acid and 2.25mgl−1 benzyl adenine produced ellagitannins found in intact plants of the Tamaricaceae. This was demonstrated by the isolation of 14 monomeric–tetrameric ellagitannins from the aq. Me2CO extract of the cultured tissues. This is the first report on the production of ellagitannin tetramers by plant tissue culture. The effects of light and certain medium constituents on tissue growth and ellagitannin production were examined. The contents of representative tannins of different types [i.e., tellimagrandin II (monomer), hirtellin A (linear GOG-type dimer), hirtellin B (hellinoyl-type dimer), hirtellin C (macrocyclic-type dimer), and hirtellin T1 (linear GOG-type trimer)] in the resultant tissues in response to these factors were estimated by HPLC, and the optimal condition for production of these tannins were established. Shoots cultured on LS hormone-free medium promoted root development, and regenerated plants could adapt to ordinary soil and climate. Acclimatized and intact T. tetrandra plants that were collected in November and May, respectively, demonstrated seasonal differences in individual ellagitannin contents. HPLC comparison of individual ellagitannin contents in different plant materials (i.e., leaves, stems, and roots) of intact T. tetrandra plants is also reported. The results are discussed with respect to cellular deposition and biosynthetic relationship of tannins. [Copyright &y& Elsevier]

Abstract: An ellagitannin monomer, nilotinin M1 (1), and three dimers, nilotinins D1 (2), D2 (3), and D3 (4), were isolated from leaves of Tamarix nilotica (Ehrenb.) Bunge. Structures were elucidated based on analysis of spectroscopic data and chemical correlations with known compounds. In addition, six known tannins, hirtellin A (5) (dimer), remurin A (6), remurin B (7), 1,3-di-O-galloyl-4,6-O-(S)-hexahydroxydiphenoyl-β-d-glucose (8), gemin D (9), and hippomanin A (10) (monomers), were isolated for the first time from this plant species. The reported 13C NMR assignments of the dehydrodigalloyl moiety and glucose cores of 5 are revised, and the 13C NMR spectroscopic data for 6 and 7 are also reported for the first time. [Copyright &y& Elsevier]

Investigation on tannins having antitumor properties led to the isolation of two new C -glycosidic ellagitannins (1 and 2) along with seven known ellagitannins (3 – 9) and a related polyphenolic constituent (10) from Lawsonia inermis leaves. Our intensive HRESIMS, 1D and 2D NMR, and ECD spectroscopic studies of new tannins have shown that one (1) has a monomer structure of C -glycosidic tannin, and the other (2) has a dimeric structure of 2,3- O -hexahydroxydiphenoyl glucopyranose and a C -glycosidic tannin. Among the known compounds, one (3) is a C -glycosidic tannin that was isolated first of all from nature, five were C -glycosidic tannins, vescalagin (4), 1- O -methylvescalagin (5), castalagin (6), stachyurin (7), and casuarinin (8), and one was an O- glycosidic ellagitannin, tellimagrandin II (9). The remaining phenolic constituent from the leaves was identified as valoneic acid dilactone (10). The ellagitannins 1 , and 3 – 9 demonstrated noticeable cytotoxicity on human oral squamous cell carcinoma cell lines (HSC-2, HSC-4, and Ca9–22), and lower effects on human oral normal cells (HGF, HPC, and HPLF). Tellimagrandin II (9) had the highest tumor-specific cytotoxicity, and also cleaved poly (ADP-ribose) polymerase 1 in HSC-2 cells. These findings showed that L. inermis ellagitannins may be a candidate for the production of anti-oral cancer materials. [Display omitted] • Two new (1 and 2), a first isolated from nature (3), and six knowns (4 – 9) ellagitannins, and a related phenolic (10) were isolated from leaves of L. inermis. • The ellagitannins (1 , 3 – 9) exhibited higher cytotoxicity against human oral cancer cell lines (HSC-2, HSC-4, and Ca9–22) than against human normal oral cells (HGF, HPC, and HPLF). • Tellimagrandin II (9) induced cleavage of PARP1 in HSC-2 cells. [ABSTRACT FROM AUTHOR]

Four flavanolignans, ceibapentains A (1) and B (2) and cinchonains Ia (3) and Ib (4), were isolated for the first time from an ethyl acetate extract of Ceiba pentandra (L) (Bombacaceae) aerial parts. The ceibapentains A (1) and B (2) are new compounds and their structures, including the absolute configurations, were determined by HRESIMS, 1D and 2D NMR, and electronic circular dichroism analyses, then compared with reported data. Compounds 1 – 4 were tested for their anti-Alzheimer's activity via an assessment of their inhibitory effect on amyloid β 42 aggregation using a thioflavin T assay. The results revealed that cinchonain Ia (3) showed a higher inhibitory effect (91%) than the standard curcumin (70%). Compounds 1 , 2 , and 4 exhibited moderate activity, with inhibition ratios of 43%, 47%, and 58%, respectively. A molecular docking study on the binding mode of 3 and curcumin with an amyloid β 1–40 peptide fibril structure indicated a high affinity of cinchonain 1a (3) towards amyloid β 1–40 peptide, in agreement with the experimental results. Unlabelled Image • Isolation of two new and two known flavanolignans from Ceiba pentandra • Investigation of the anti-Alzheimer's activities of the isolated compounds • Assessment of their inhibitory effect on amyloid β 42 aggregation • Molecular docking study on the binding mode of compounds with amyloid β 1–40 [ABSTRACT FROM AUTHOR]

The methanolic extract and its sub-extracts (viz , n –hexane, DCM, EtOAc and MeOH) of the soft coral Sarcophyton acutum were evaluated as anti- Leishmania major and as anticancer (against the HepG2, MCF-7, and A549 cell lines) using the MTT assay. Six polyhydroxy sterols (1–6) were isolated from the most active cytotoxic and anti-leishmanial EtOAc-soluble fraction. Their structures were established as two new polyhydroxy sterols, acutumosterols A (1) and B (2), and four known structural analogues (3 – 6) by intensive spectroscopic analyses, and by comparison with data of related compounds. Compound 4 exerted noticeable cytotoxicity against HepG2 cell line (IC 50 17.2 ± 1.5 μg/mL), while the other pure isolates showed weak to moderate cytotoxicity (24.8 ± 2.8–57.2 ± 5.2). The results were discussed in relation to the structural features of these closely related sterols. Unlabelled Image • The anti- Leishmania major and cytotoxic activities (against HepG2, MCF-7, and A549 cell lines) of the Red Sea soft coral Sarcophyton acutum were evaluated. • Two new, acutumosterols A (1) and B (2), and four known (3 – 6) polyhydroxy sterols were isolated from the most active ethyl acetate fraction. • Cytotoxicity and anti- L. major activities of the pure isolates (1 – 6) were evaluated. [ABSTRACT FROM AUTHOR]