UPLC-ESI-MS/MS Profiling of Secondary Metabolites from Methanol Extracts of In Vivo and In Vitro Tissues of Daucus capillifolius Gilli (A Comparative Study).

Daucus capillifolius Gilli is a rare annual wild herb grown in Libya. It belongs to the Apiaceae family, which is one of the largest flowering plant families. Plants of this family are outstanding sources of various secondary metabolites with various biological activities. A UPLC-ESI-MS/MS analysis of different extracts of in vivo and in vitro tissues of Daucus capillifolius together with the fruit extract of the cultivated plant in both ionization modes was carried out for the first time in the current study. Our results reveal the tentative identification of eighty-seven compounds in the tested extracts, including thirty-two phenolic acids and their derivatives; thirty-seven flavonoid glycosides and aglycones of apigenin, luteolin, diosmetin, myricetin and quercetin, containing glucose, rhamnose, pentose and/or glucuronic acid molecules; seven anthocyanins; six tannins; three acetylenic compounds; and three nitrogenous compounds. The tentative identification of the above compounds was based on the comparison of their retention times and ESI-MS/MS fragmentation patterns with those previously reported in the literature. For this Apiaceae plant, our results confirm the presence of a wide array of secondary metabolites with reported biological activities. This study is among the first ones to shed light on the phytoconstituents of this rare plant.

Investigation of phytochemicals isolated from selected Saudi medicinal plants as natural inhibitors of SARS CoV-2 main protease: In vitro, molecular docking and simulation analysis.

The escalation of many coronavirus variants accompanied by the lack of an effective cure has motivated the hunt for effective antiviral medicines. In this regard, 18 Saudi Arabian medicinal plants were evaluated for SARS CoV-2 main protease (Mpro) inhibition activity. Among them, Terminalia brownii and Acacia asak alcoholic extracts exhibited significant Mpro inhibition, with inhibition rates of 95.3 % and 95.2 %, respectively, at a concentration of 100 µg/mL. Bioassay-guided phytochemical study for the most active n-butanol fraction of T. brownii led to identification of eleven compounds, including two phenolic acids (1, and 2), seven hydrolysable tannins (3-10), and one flavonoid (11) as well as four flavonoids from A. asak (12-15). The structures of the isolated compounds were established using various spectroscopic techniques and comparison with known compounds. To investigate the chemical interactions between the identified compounds and the target Mpro protein, molecular docking was performed using AutoDock 4.2. The findings identified compounds 4, 5, 10, and 14 as the most potential inhibitors of Mpro with binding energies of -9.3, -8.5, -8.1, and -7.8 kcal mol-1, respectively. In order to assess the stability of the protein-ligand complexes, molecular dynamics simulations were conducted for a duration of 100 ns, and various parameters such as RMSD, RMSF, Rg, and SASA were evaluated. All selected compounds 4, 5, 10, and 14 showed considerable Mpro inhibiting activity in vitro, with compound 4 being the most powerful with an IC50 value of 1.2 µg/mL. MM-GBSA free energy calculations also revealed compound 4 as the most powerful Mpro inhibitor. None of the compounds (4, 5, 10, and 14) display any significant cytotoxic activity against A549 and HUVEC cell lines.

Cichorins D-F: Three New Compounds from Cichorium intybus and Their Biological Effects.

Cichorium intybus L., (chicory) is employed in various traditional medicines to treat a wide range of diseases and disorders. In the current investigation, two new naphthalane derivatives viz., cichorins D (1) and E (2), along with one new anthraquinone cichorin F (3), were isolated from Cichorium intybus. In addition, three previously reported compounds viz., ß-sitosterol (4), ß-sitosterol ß-glucopyranoside (5), and stigmasterol (6) were also isolated from Cichorium intybus. Their structures were established via extensive spectroscopic data, including 1D (1H and 13C) and 2D NMR (COSY, HSQC and HMBC), and ESIMS. Cichorin E (2) has a weak cytotoxic effect on breast cancer cells (MDA-MB-468: IC50: 85.9 µM) and Ewing's sarcoma cells (SK-N-MC: IC50: 71.1 µM); cichorin F (3) also illustrated weak cytotoxic effects on breast cancer cells (MDA-MB-468: IC50: 41.0 µM and MDA-MB-231: IC50: 45.6 µM), and SK-N-MC cells (IC50: 71.9 µM). Moreover compounds 1-3 did not show any promising anthelmintic effects.

Persicaline, A New Antioxidant Sulphur-Containing Imidazoline Alkaloid from Salvadora persica Roots.

Salvadora persica L. is a popular chewing stick commonly known as "miswak". During our ongoing research activities on the chemical constituents of Salvadora persica roots, which is a new sulphur-containing imidazoline alkaloid 1,3-Dibenzyl-4-(1,2,3,4-tetrahydroxy-butyl)-1,3-dihydro-imidazole-2-thione, persicaline, (1) along with five known compounds (2-6) are identified. Compounds (2, 3) were reported for the first time from the family Salvadoraeceae. The structure of the new compound was established by extensive spectroscopic data and HR-MS. The antioxidant activities of the fractions and isolates were evaluated using different in vitro methods, such as DPPH, superoxide anion and nitric oxide radicals scavenging assays. Compound (1) showed a promising antioxidant activity with IC50 0.1, 0.08, and 0.09 µM in the three assays, respectively, comparable to ascorbic acid.

New Cytotoxic Seco-Type Triterpene and Labdane-Type Diterpenes from Nuxia oppositifolia.

Chromatographic purification of the n-hexane and dichloromethane extracts of Nuxia oppositifolia aerial parts, growing in Saudi Arabia, resulted in the isolation and characterization of three new labdane-type diterpene acids, 2ß-acetoxy-labda-7-en-15-oic acid (1), 2ß-acetoxy-7-oxolabda-8-en-15-oic acid (2), 2ß-acetoxy-6-oxolabda-7-en-15-oic acid (3), and one new seco-triterpene, 3,4-seco olean-12-en-3,30 dioic acid (4), together with 10 known lupane, oleanane and ursane-type triterpenes, as well as the common phytosterols, ß-sitosterol and stigmasterol (5-16). Their structures have been assigned on the basis of different spectroscopic techniques including 1D and 2D NMR. Moreover, 13 of the isolated compounds were tested on the human cancer cell lines HeLa (cervical), A549 (lung) and MDA (breast), and most of the compounds showed potent cytotoxic activities in vitro.

Comparative study of antioxidant activity and validated RP-HPTLC analysis of rutin in the leaves of different Acacia species grown in Saudi Arabia.

The present study assessed the comparative antioxidant potential of the ethanol extract (EE) of leaves of four Acacia species (Acacia salicina, AS; Acacia laeta, AL; Acacia hamulosa AH; and Acacia tortilis, AT) grown in Saudi Arabia, including RP-HPTLC quantification of antioxidant biomarker rutin. In vitro DPPH radical scavenging and ß-carotene-linoleic acid bleaching assays showed the promising antioxidant activities of Acacia extracts: ASEE (IC50: 60.39 and 324.65 µg/ml) >ALEE (IC50: 217.06 and 423.36 µg/ml) >ATEE (IC50: 250.13 and 747.50 µg/ml) >AHEE (IC50: 255.83 and 417.28 µg/ml). This was comparable to rutin tested at 500 µg/ml. Further, a RP- HPTLC densitometric method was developed (acetonitrile:water; 6:4; v/v) using glass-backed RP-18 silica gel F254 plate, and scanned at UV max 254 nm. The method was validated as per the ICH guidelines. Analysis of the validated RP-HPTLC displayed an intense peak (Rf = 0.65 ± 0.004) of rutin that was estimated (µg/mg dry weight) to be highest in ASEE (10.42), followed by ALEE (2.67), AHEE (1.36) and ATEE (0.31). Taken together, presence of rutin strongly supported the high antioxidant property of the tested Acacia species, especially Acacia salicina. The developed RP-HPTLC method therefore, affirms its application in the quality control of commercialized herbal drugs or formulation containing rutin.

New acyclic secondary metabolites from the biologically active fraction of Albizia lebbeck flowers.

The total extract of Albizia lebbeck flowers was examined in vivo for its possible hepatoprotective activity in comparison with the standard drug silymarin at two doses. The higher dose expressed promising activity especially in reducing the levels of AST, ALT and bilirubin. Fractionation via liquid-liquid partition and reexamination of the fractions revealed that the n-butanol fraction was the best in improving liver biochemical parameters followed by the n-hexane fraction. However, serum lipid parameters were best improved with CHCl3 fraction. The promising biological activity results initiated an intensive chromatographic purification of A. lebbeck flowers fractions. Two compounds were identified from natural source for the first time, the acyclic farnesyl sesquiterpene glycoside1-O-[6-O-α-l-arabinopyranosyl-ß-d-glucopyranoside]-(2E,6E-)-farnesol (6) and the squalene derivative 2,3-dihydroxy-2,3-dihydrosqualene (9), in addition to eight compounds reported here for the first time from the genus Albizia; two benzyl glycosides, benzyl 1-O-ß-d-glucopyranoside (1) and benzyl 6-O-α-l-arabinopyranosyl ß-d-glucopyranoside (2); three acyclic monoterpene glycosides, linalyl ß-d-glucopyranoside (3) and linalyl 6-O-α-l-arabinopyranosyl-ß-d-glucopyranoside (4); (2E)-3,7-dimethylocta-2,6-dienoate-6-O-α-l arabinopyranosyl-ß-d-glucopyranoside (5), two oligoglycosides, n-hexyl-α-l arabinopyranosyl-(1 â†’ 6)-ß-d-glucopyranoside (creoside) (7) and n-octyl α-l-arabinopyranosyl-(1 â†’ 6)-ß-d-glucopyranoside (rhodiooctanoside) (8); and ethyl fructofuranoside (10). The structures of the isolated compounds were elucidated based on extensive examination of their spectroscopic 1D and 2D-NMR, MS, UV, and IR data. It is worth mentioning that, some of the isolated linalol glycoside derivatives were reported as aroma precursors.

Comparative anticancer and antimicrobial activity of aerial parts of Acacia salicina, Acacia laeta, Acacia hamulosa and Acacia tortilis grown in Saudi Arabia.

The standardized ethanol extract (EE) of aerial parts of four Acacia species [A. salicina (ASEE), A. laeta (ALEE), A. hamulosa (AHEE), and A. tortilis (ATEE)] were examined in order to compare their cytotoxic and antimicrobial activities. All the extracts were standardized by UPLC- PDA method using rutin as standard compound. The extracts ALEE, AHEE and ATEE were found to contain rutin along with several other phytoconstituents while rutin was absent in ASEE. All the extracts showed varying level of antimicrobial activity with zone of inhibition ranged from 11 to 21 mm against Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Candida albicans. The ALEE and ATEE showed relatively high antimicrobial potency (MIC = 0.2 to 1.6 mg mL-1) in comparison to other extracts. All the extracts were found to reduce the biofilm of P. aeruginosa PAO1 strain significantly in comparison to the untreated control. The cytotoxic property of ASEE, ALEE, AHEE, ATEE were evaluated against HepG2 (Liver), HEK-293 (Kidney), MCF-7 (Breast) and MDA-MB 231 (Breast) cancer cells. Of these, ALEE, AHEE and ATEE exhibited moderate cytotoxic property against human liver carcinoma cells (HepG2; IC50 = 46.2, 39.2 and 42.3 µg mL-1, respectively) and breast cancer cell lines (MCF-7; IC50 = 57.2, 55.3 and 65.7 µg mL-1, respectively). The ATEE and ALEE showed moderate cytotoxicity against HEK-293 (kidney) cells with IC50 = 49.1 and 53.5 µg mL-1, respectively. Since, Acacia species (A. laeta and A. hamulosa) contains numerous polyphenols which might prove to be highly cytotoxic and antimicrobial agents, we suggest that these species can be further subjected to the isolation of more cytotoxic and antimicrobial compounds.

Antioxidant study of flavonoid derivatives from the aerial parts of Rhus natalensis growing in Saudi Arabia.

Phytochemical study of the CH(2)Cl(2) soluble fraction of the aerial parts of R. natalensis resulted in the isolation and identification of six flavonoid derivatives, ß-amyrin and ß-sitosterol glucoside (daucosterol). The isolated compounds were identified utilizing physical, chemical and different spectral methods including UV, 1D- 2D-NMR and MS. The compounds were identified as four flavanones; 7-O-methyl hesperetin (1), 7-O-methyl naringenin (4), (-)-homoeriodictyol (eriodictyonone) (5), eriodictyol-7-methyl ether (6) and two flavones; 7-O-methyl isokaemferide (2) and genkwanin (3). The isolated compounds as well as some available standards representing structurally similar flavones and flavanones were used to study their antioxidant potential using DPPH and try to explore the impact of structures on the antioxidant activity. In other assays flavanones were less active than flavones as antioxidant due to lack of the C-4 carbonyl group in conjugation with 2,3-double bond. However, in DPPH assay based on the ability of molecules to donate hydrogen flavanones were found more active than flavones.

Quantitative analysis of biomarker rutin in different species of genus Ficus by validated NP and RP-HPTLC methods.

Biomarker rutin was analyzed in methanol extracts of leaves of five different species of genus Ficus (Ficus carica, Ficus nitida, Ficus ingens, Ficus palmata and Ficus vasta) by NP-HPTLC (Method I) and RP- HPTLC methods (Method II). The development and validation for method I was carried out with silica gel 60F254 plates using EA: GAA: FA: H2O (10:1:1:2.5, v/v/v/v) as developing system. Method II was carried out on silica gel 60F254 RP-18 plates using mobile phase ACN: H2O (4:6 v/v). Both analyses were scanned at 305 nm and were found to give well resolved peak of rutin at Rf0.28±0.01 and 0.68±0.03 for Method I and Method II, respectively. The percentage of rutin was found to be 0.51% & 0.66% in F. ingens, 0.24% & 0.54% in F. palmata and 0.14% & 0.17% in F. vasta by Method I & Method II, respectively. Method II (RP-HPTLC) was found to be more accurate, precise and sensitive than Method I. Method II can be used as an important tool for standardization and quality control of bulk drugs and in-process formulations of rutin.

Densitometric validation and analysis of biomarker ß-amyrin in different Acacia species (leaves) grown in Kingdom of Saudi Arabia by high performance thin-layer chromatography.

Biomarker ß-amyrin was analyzed in the leaves of four different Acacia species (A. salicina, A. loreta, A. hamulosa and A. tortilis) grown in Kingdom of Saudi Arabia by a validated HPTLC method. The chromatography was performed on glass-backed silica gel 60 F254 HPTLC plates using solvents toluene: methanol (9:1, v/v) as mobile phase. The developed TLC plate was derivatized with anisaldehyde and scanned at 520 nm. A sharp peak of ß-amyrin was found at Rf=0.58±0.01. The r2 and the linear regression equation for ß-amyrin was found to be 0.991 and 19.913X+107.803, respectively in the concentration range of 100-800 ng. The percentage of ß-amyrin was found to be maximum 2.70% w/w in A. tortilis, 1.85% w/w in A. loreta and 1.80% w/w in A. hamulosa while it was totally absent in A. salicina. This study conceives maiden reporting of quantification of ß-amyrin in four different species of Acacia by validated HPTLC method. The developed method for the analysis of ß-amyrin was proved to be reproducible by statistical analysis hence it can be employed for further analysis of ß-amyrin in plasma, other biological fluids and in finished products available in the market.

Quantification of glycyrrhizin in anti-stress herbal formulations by validate HPTLC method: a rational paradigm towards quality control of herbals.

In the present study an analytical method of high-performance thin-layer chromatography (HPTLC) has been developed for quantification of glycyrrhizin for marketed antistressliquorice root capsules (LRC) and herbal tea (HT). Chromatography was performed by using mobile phase ethyl acetate (EA): glacial acetic acid (GAA): Methanol (MeOH): water (H(2)O) in proportion of 6:2:2:1, v/v/v/v. The developed plate was scanned and quantified densitometrically at absorption maxima 254nm. The method was validated for various analytical parameters viz. precision, accuracy, recovery, robustness, specificity, detection and quantification limits. The developed system was found to give compact spot for glycyrrhizin (R(f)= 0.33± 0.001). The linearity relationship was described by the equation Y=6.841X+ 70.428. The limit of detection (34 ng band(-1)), limit of quantification (101 ng band(-1)), recovery (99.4-99.8%), and precision (<1.84% and <1.62%; intraday and interday, respectively) were found satisfactory for glycyrrhizin. Linearity range for glycyrrhizin was 100-600ng (r(2)=0.998). The amount of glycyrrhizin was estimated by comparing the peak area of standard and the same was present in crude extract. The content of glycyrrhizin was estimated as 11.4% and 4.7% w/w in sample LRC and HT, respectively. The proposed method will be useful to quantify the therapeutic dose of glycyrrhizin in herbal formulations as well as in bulk drug.

A novel ß-lactam derivative, albactam from the flowers of Albizia lebbeck with platelets anti-aggregatory activity in vitro.

A novel ß-lactam derivative, albactam, was isolated from the alcoholic extract of the flowers of Albizia lebbeck. It showed a significant anti-aggregatory activity against adenosine diphosphate and arachidonic acid induced guinea-pigs' platelets aggregation in vitro. Six more known compounds were also isolated and fully characterized by measuring 1D and 2D NMR, two of them are the triterpenes ß-amyrin and 11α, 12α-oxidotaraxerol, two ceramide derivatives and two flavonoids, kampferol 3-O-rutinoside and rutin.

A novel 6-hydroxy-8,11,11-trimethyl-bicyclo[7.2.0]undec-4-ene-4-carboxylic acid: a potent antioxidant agent from Iphiona scabra.

A novel 6-hydroxy-8,11,11-trimethyl-bicyclo[7.2.0]undec-4-ene-4-carboxylic acid 1 has been isolated from leaves of Iphiona scabra DC. Its structure has been established on the basis of chemical and physical evidence (IR, ¹H NMR, ¹³C NMR, and MS) and further confirmed by single-crystal X-ray diffraction study. The in vitro antioxidant activities of isolated compound 1 and extracts were evaluated by 1,1-diphenyl-2-picrylhydrazyl method.

Phytochemical and pharmacological study of Ficus palmata growing in Saudi Arabia.

Phytochemical study of the aerial parts of Ficus palmata utilizing liquid-liquid fractionation and different chromatographic techniques resulted in the isolation of a new isomer of psoralenoside namely, trans-psoralenoside (5) in addition to, one triterpene: germanicol acetate (1), two furanocoumarins: psoralene (2), bergapten (3), one aromatic acid vanillic acid (4) and the flavone glycoside rutin (6). Structures of the isolated compounds were established through physical, 1D- and 2D-NMR and MS data. The total extract and fractions of the plant were examined in vivo for its possible effects as hepatoprotective, nephroprotective, antiulcer and anticoagulant activities in comparison with standard drugs. Hepatoprotective activity was assessed via serum biochemical parameters including aspartate aminotransferase (AST), alanine aminotransferase (ALT), gamma glutamyl transpeptidase (GGT), alkaline phosphatase (ALP) and total bilirubin. Tissue parameters such as non-protein sulfhydryl groups (NP-SH), malonaldehyde (MDA) and total protein (TP) were also measured. In addition to tissue parameters, nephroprotective effect was evaluated by measuring the serum levels of sodium, potassium, creatinine and urea. Histopathological study for both liver and kidney cells was also conducted. Antiulcer activity was explored by observing stomach lesions after treatment with ethanol. Whole blood clotting time (CT) was taken as a measure for the anticoagulant activity of the extract. Antioxidant activity of the total extract and fractions of the plant was measured using 2,2-diphenyl-1-picrylhydrazyl (DPPH) method and ascorbic acid as standard.

Chemical and Biological Characterization of the Ethyl Acetate Fraction from the Red Sea Marine Sponge Hymedesmia sp.

Hymedesmiidae is one of the largest families of marine sponges and stands out as an exceptional source of variable metabolites with diverse biological activities. In this study, the ethyl acetate fraction (HE) of a Hymedesmia sp. marine sponge from the Red Sea, Egypt, was analyzed for the first time using Ultra-performance liquid chromatography electrospray ionization tandem mass spectrometry (UPLC-ESI-MS/MS) analysis. The analysis tentatively identified 29 compounds in this fraction, including the isolation and identification of six compounds (two pyrimidine nucleosides, one purine, and two pyrimidine bases in addition to one cerebroside) for the first time. The structures of the isolated compounds were established by 1D and 2D NMR (nuclear magnetic resonance), MS (mass spectrometry), and IR (infrared) spectroscopy. Furthermore, the cytotoxic, antioxidant, and antimicrobial activities of the ethyl acetate fraction were evaluated in vitro. The fraction exhibited strong DPPH scavenging activity with an IC50 of 78.7 µg/mL, compared to ascorbic acid as a positive control with an IC50 of 10.6 µg/mL. It also demonstrated significant cytotoxic activity with IC50 values of 13.5 µg/mL and 25.3 µg/mL against HCT-116 and HEP-2 cell lines, respectively, compared to vinblastine as a positive control with IC50 values of 2.34 µg/mL and 6.61 µg/mL against HCT-116 and HEP-2, respectively. Additionally, the ethyl acetate fraction displayed promising antibacterial activity against S. aureus with a MIC value of 62.5 µg/mL, compared to ciprofloxacin as a positive control with MIC values of 1.56 µg/mL for Gram-positive bacteria and 3.125 µg/mL for Gram-negative bacteria. It also exhibited activity against E. coli and P. aeruginosa with MIC values of 250 µg/mL and 500 µg/mL, respectively. Briefly, this is the first report on the biological activities and secondary metabolite content of the ethyl acetate fraction of Hymedesmia sp. marine sponge, emphasizing the potential for further research against resistant bacterial and fungal strains, as well as different cancer cell lines. The ethyl acetate fraction of Hymedesmia sp. is a promising source of safe and unique natural drugs with potential therapeutic and pharmaceutical benefits.

Phytochemical, antimicrobial and antiprotozoal evaluation of Garcinia mangostana pericarp and α-mangostin, its major xanthone derivative.

Five xanthone derivatives and one flavanol were isolated from the dichloromethane extract of Garcinia mangostana. Dichloromethane, ethyl acetate extract and the major xanthone (α-mangostin) were evaluated in vitro against erythrocytic schizonts of Plasmodium falciparum, intracellular amastigotes of Leishmania infantum and Trypanosoma cruzi and free trypomastigotes of T. brucei. The major constituent α-mangostin was also checked for antimicrobial potential against Candida albicans, Escherichia coli, Pseudomonas aeruginosa, Bacillius subtilis, Staphylococcus aureus, Mycobacterium smegmatis, M. cheleneoi, M. xenopi and M. intracellulare. Activity against P. falciparum (IC50 2.7 µg/mL) and T. brucei (IC50 0.5 µg/mL) were observed for the dichloromethane extract, however, with only moderate selectivity was seen based on a parallel cytotoxicity evaluation on MRC-5 cells (IC50 9.4 µg/mL). The ethyl acetate extract was inactive (IC50 > 30 µg/mL). The major constituent α-mangostin showed rather high cytotoxicity (IC50 7.5 µM) and a broad but non-selective antiprotozoal and antimicrobial activity profile. This in vitro study endorses that the antiprotozoal and antimicrobial potential of prenylated xanthones is non-conclusive in view of the low level of selectivity.

Virtual screening and molecular dynamics simulation study of abyssomicins as potential inhibitors of COVID-19 virus main protease and spike protein.

The lack of any effective cure for the infectious COVID-19 disease has created a sense of urgency and motivated the search for effective antiviral drugs. Abyssomicins are actinomyces-derived spirotetronates polyketides antibiotics known for their promising antibacterial, antitumor, and antiviral activities. In this study, computational approaches were used to investigate the binding mechanism and the inhibitory ability of 38 abyssomicins against the main protease (Mpro) and the spike protein receptor-binding domain (RBD) of the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). The results identified abyssomicins C, J, W, atrop-O-benzyl abyssomicin C, and atrop-O-benzyl desmethyl abyssomicin C as the most potential inhibitors of Mpro and RBD with binding energy ranges between -8.1 and -9.9 kcal mol-1; and between -6.9 and -8.2 kcal mol-1, respectively. Further analyses of physicochemical properties and drug-likeness suggested that all selected active abyssomicins, with the exception of abyssomicin J, obeyed Lipinski's rule of five. The stability of protein-ligand complexes was confirmed by performing molecular dynamics simulation for 100 ns and evaluating parameters such as such as root mean square deviation (RMSD), root mean square fluctuation (RMSF), radius of gyration (Rg), solvent accessible surface area (SASA), total number of contacts, and secondary structure. Prime/MM-GBSA (Molecular Mechanics-General Born Surface Area) and principal component analysis (PCA) analyses also confirmed the stable nature of protein-ligand complexes. Overall, the results showed that the studied abyssomicins have significant interactions with the selected protein targets; therefore, they were deemed viable candidates for further in vitro and in vivo evaluation.Communicated by Ramaswamy H. Sarma.

Chemical constituents from Centaurothamnus maximus and their antimicrobial activity.

A new sesquiterpene lactone, 3ß,10α-dihydroxy-10ß-(hydroxymethyl)-8α-(4-hydroxymethacrylate)-1αH,5αH,6ßH,7αH-guai-4(15), 11(13)-dien-6,12-olide (1), along with twenty-one known compounds, were identified from the aerial parts of Centaurothamnus maximus. The structures of the isolated compounds were elucidated on the basis of spectroscopic evidences and correlated with known compounds. Compounds (2, 3, 5‒13 and 15‒22) were identified from C. maximus for the first time. Antibacterial and antifungal activities of the isolated compounds were tested using the agar disc diffusion method. Compounds that demonstrated promising antimicrobial activity were evaluated for their minimum inhibitory concentration (MIC). The results showed that compounds 3 and 7 were the most effective antibacterial compounds against B. subtilis ATCC 6633, S. aureus ATCC 25923 and S. pyogenes ATCC 27736, with MIC estimates between 8 and 32 mg/mL. In addition, compound 2 exhibited the strongest antifungal activity against C. albicans ATCC 14243 and C. krusei ATCC 14243 with MIC 8 mg/mL.

Twenty-two compounds were first isolated from Centaurothamnus maximusThe structure of the new sesquiterpene lactone, thamnolide (1), was established.Antibacterial and antifungal activities were tested for the isolated compounds.Compounds 3 and 7 were the strongest antibacterial compounds whilst 2 exhibited the strongest antifungal activity.

Biomarker Quantification, Spectroscopic, and Molecular Docking Studies of the Active Compounds Isolated from the Edible Plant Sisymbrium irio L.

Phytochemical investigation of the ethanolic extract of the aerial parts of Sisymbrium irio L. led to the isolation of four unsaturated fatty acids (1-4), including a new one (4), and four indole alkaloids (5-8). The structures of the isolated compounds were characterized with the help of spectroscopic techniques such as 1D, 2D NMR, and mass spectroscopy, and by correlation with the known compounds. In terms of their notable structural diversity, a molecular docking approach with the AutoDock 4.2 program was used to analyze the interactions of the identified fatty acids with PPAR-γ and the indole alkaloids with 5-HT1A and 5-HT2A, subtypes of serotonin receptors, respectively. Compared to the antidiabetic drug rivoglitazone, compound 3 acted as a potential PPAR-γ agonist with a binding energy of -7.4 kcal mol-1. Moreover, compound 8 displayed the strongest affinity, with binding energies of -6.9 kcal/mol to 5HT1A and -8.1 kcal/mol to 5HT2A, using serotonin and the antipsychotic drug risperidone as positive controls, respectively. The results of docked conformations represent an interesting target for developing novel antidiabetic and antipsychotic drugs and warrant further evaluation of these ligands in vitro and in vivo. On the other hand, an HPTLC method was developed to quantify α-linolenic acid in the hexane fraction of the ethanol extract of S. irio. The regression equation/correlation coefficient (r2) for linolenic acid was Y = 6.49X + 2310.8/0.9971 in the linearity range of 100-1200 ng/band. The content of α-linolenic acid in S. irio aerial parts was found to be 28.67 µg/mg of dried extract.