Seasonal metabolic profiling of Valencia orange leaf essential oil using GC coupled with chemometrics, nano-formulation, and insecticidal evaluation: in vivo and in silico

Mosquitoes and mosquito-borne infectious diseases are a global challenge, especially with increased resistance to synthetic insecticides. The foregoing study aimed to utilize the essential oil of leaves of Citrus sinensis var. Valencia as a cheap, safe, eco-friendly (green), and effective alternative to chemical insecticides. Essential oil samples were collected from fresh and dried leaves across different seasons. They are subjected to hydrodistillation and then GC analysis to be compared. Seventy-seven compounds were detected in all samples where monoterpene hydrocarbons represented the most abundant class of hydrocarbons in fresh leaves (52.6-74.4%) and dried leaves (58.6-66.9%). Sabinene (8.26-29.2%), delta-3-carene (8.23-16.4%), d-limonene (2.50-11.2%), and β-myrcene (2.40-4.93%) were the major monoterpene hydrocarbons in all seasons. Oxygenated monoterpenes comprising β-linalool, citronellal, terpinen-4-ol, β-citral, and α-citral exhibited also appreciable percentages in fresh (21.2-43.4%) and dried leaves (23.4-33.0%). Hierarchical cluster analysis (HCA) and principal component analysis (PCA) effectively segregated all samples into three discriminate clusters where, β-linalool, terpinen-4-ol, β-elemene enantiomer, sabinene, and β-phellandrene constitute the main discriminatory biomarkers. Essential oil of fresh spring leaves (FS) was chosen for nano-formulation adopting the hot emulsification method. Both FS sample and the prepared nano-hexosomal formula were screened against the 3rd instar larvae Culex pipiens L. (common house mosquito). LC₅₀ and LC₉₅ values of FS and oil loaded nano-formula were (48 and 30 552 mg L^-1) and (30 and 1830 mg L^-1) respectively. α-Citral followed by citronellal showed the best fitting within the binding sites of acetylcholine esterase enzyme utilizing molecular docking. Thus, it can be concluded that Valencia orange leaf as a nano-formulation could serve as an effective and sustainable insecticidal agent.

Hesperidin hexosomal loaded nanodispersion: insights of its antimycobacterial, cytotoxic and anti-HCoV effects

Fruits of Citrus sinensis L. Osbeck var. Valencia contain hesperidin as a major flavanone glycoside. Hesperidin (H) was isolated from the peels of Valencia orange and formulated as hexosomal nanodispersions (F1) adopting the hot emulsification method. The antimycobacterial activity(anti-TB) was evaluated through a microplate Alamar blue (MABA) assay where F1 showed significant activity with MIC = 0.19 µM. To unravel the potential mechanism of the anti-TB, a molecular docking study of H using the Mycobacterial Dihydrofolate reductase (Mtb. DHFR) enzyme was performed. Hesperidin exhibited significant interactions with Mtb. DHFR active site. Sulforhodamine B assay was applied to evaluate cytotoxic activity against the lung cancer cell line (A-549). F1 showed a cytotoxic effect at IC₅₀= 33 µM. It also has potent antiviral activity against Human Coronavirus 229E with IC₅₀= 258.8 μM utilising crystal violet assay. Peels of Valencia orange could be a source of bioactive metabolites to control significant diseases.

Cattleianal and Cattleianone: Two New Meroterpenoids from Psidium cattleianum Leaves and Their Selective Antiproliferative Action against Human Carcinoma Cells

The Myrteacae family is known as a rich source of phloroglucinols, a group of secondary metabolites with notable biological activities. Leaves of Psidium cattleianum were extracted with chloroform: methanol 8:2 to target the isolation of phloroglucinol derivatives. Isolated compounds were characterized using different spectroscopic methods: nuclear magnetic resonance (NMR), ultra-violet (UV) and mass spectrometry (MS). Two new phloroglucinols were evaluated for cytotoxicity against a panel of six human cancer cell lines, namely colorectal adenocarcinoma cells (HT-29 and HCT-116); hepatocellular carcinoma cells (HepG-2); laryngeal carcinoma (Hep-2); breast adenocarcinoma cells (MCF7 and MDA-MB231), in addition to normal human melanocytes HFB-4. Additionally, cell cycle analysis and annexin-V/FITC-staining were used to gain insights into the mechanism of action of the isolated compounds. The new phloroglucinol meroterpenoids, designated cattleianal and cattleianone, showed selective antiproliferative action against HT-29 cells with IC₅₀’s of 35.2 and 32.1 μM, respectively. Results obtained using cell cycle analysis and annexin-V/FITC-staining implicated both necrosis and apoptosis pathways in the selective cytotoxicity of cattleianal and cattleianone. Our findings suggest that both compounds are selective antiproliferative agents and support further mechanistic studies for phloroglucinol meroterpenoids as scaffolds for developing new selective chemotherapeutic agents.

Chemical composition and bioactivity of the volatile oil from leaves and stems of Eucalyptus cinerea

CONTEXT

Eucalyptus cinerea F. Muell. ex Benth. (Myrtaceae) is a medium-sized tree cultivated in Egypt.

OBJECTIVE

First, to determine the chemical composition of the volatile oil of the juvenile leaves and stems of E. cinerea to identify its chemotype. Second, to study the in vivo antioxidant activity and in vitro antimicrobial activity of the studied volatile oils against selected Gram-positive, Gram-negative bacteria, yeast, and mycelia fungi.

MATERIALS AND METHODS

The volatile oil was prepared by hydrodistillation and then identified by GC/MS analysis. Broth microdilution and agar dilution methods were applied for determining the MIC. The antioxidant activity was studied by determination of glutathione level in blood of alloxan-induced diabetic rats.

RESULTS

The yield of the volatile oil hydrodistilled from the juvenile leaves and stems of E. cinerea was 4.5 and 0.5%, respectively. 1,8-Cineole was the major identified oxygenated monoterpenoid (84.55% and 60.15% in the juvenile leaves and stems, respectively). The antibacterial activity of the oil of the juvenile leaves was more potent against all the tested organisms than that of the stems. The (MIC) of volatile oil of the juvenile leaves against Escherichia coli, Pseudomonas aeruginosa, Streptococcus faecalis, Candida albicans, and Aspergillus flavus were 5.2, 5.6, 4, 4.8, and 12.8 μg/ml, respectively. Also, the juvenile leaves' oil was more active as an antioxidant than that of the stems. They restored glutathione level by 33.7 ± 1.1 and 29.6 ± 0.7 mg/dl, respectively, compared with vitamin E (35.9 ± 1.2 mg/dl) which was used as a reference.

DISCUSSION AND CONCLUSION

RESULTS suggest that the volatile oil is 1,8-cineole chemotype. Moreover, the oil of the juvenile leaves of E. cinerea might find usefulness as a therapeutic agent following further development.

Cytotoxic activity of acyl phloroglucinols isolated from the leaves of Eucalyptus cinerea F. Muell. ex Benth. cultivated in Egypt

Two acyl phloroglucinol compounds namely; Sideroxylonal B (1) and Macrocarpal A (2) were isolated from the Sideroxylonal-Rich Extract (SRE) of the juvenile leaves of Eucalyptus cinerea; F. Muell. ex Benth cultivated in Egypt. Identification of the isolated compounds was established on the basis of physico-chemical properties and spectral analysis (1D & 2D NMR). The two compounds were isolated for the first time from this species. The SRE alongside with the isolated compounds were tested against three human cancer cell lines; MCF7 (breast carcinoma cell line), HEP2 (laryngeal carcinoma), CaCo (colonic adenocarcinoma) and one type of normal human cell line;10 FS (fibroblast cells). The SRE, (1), and (2) showed cytotoxic activity with IC₅₀ 13.6 ± 0.62, 7.2 ± 0.5, 14.8 ± 0.55 μg mL−1 against HEP2 respectively, 11.6 ± 0.47, 4 ± 0.36, 11.4 ± 0.45 μg mL−1 against CaCo, respectively, and 8.6 ± 0.29, 4.4 ± 0.25, and 7.8 ± 0.3 μg mL−1 against MCF7, respectively. Meanwhile, the (SRE) together with (1) and (2) exhibited low cytotoxicity against normal cell line 10 FS, with IC₅₀ 55.4 ± 1.4, 43 ± 0.8 and 50.1 ± 1.12 μg mL−1, respectively. The antiprofilerative activity of the tested compounds was evaluated. The cell cycle profile of cells treated with Sideroxylonal-B and Macrocarpal-A indicates possible S-phase specific effects.

Antidiabetic and Antioxidant Activities of Major Flavonoids of Cynanchum acutum L. (Asclepiadaceae) Growing in Egypt

Seven flavonoids were isolated from the butanol fraction of the methanolic extract of the aerial parts of Cynanchum acutum L. (Asclepiadaceae). All of which have been isolated for the first time from the genus Cynanchum. Their structures were established as quercetin 3-O-β-galacturonopyranoside (1), quercetin 7-O-β-glucopyranoside (2), tamarixtin 3-O-β-galacturonopyranoside (3), kaempferol 3-O-β-galacturonopyranoside (4), 8-hydroxyquercetin 3-O-β-galactopyranoside (5), tamarixtin 3-O-α-rhamnopyranoside (6), and tamarixtin 7-O-α-arabinopyranoside (7) on the basis of their chromatographic properties, chemical and spectroscopic data. The major isolated flavonoids 1, 2 and 3 were found to exhibit significant antioxidant and antidiabetic activities (by measuring blood glucose and insulin levels). This is the first report about the antioxidant and antidiabetic activities of compounds 1 - 3.

Seasonal variation in the essential oil composition of Origanum majorana L. cultivated in Egypt

The hydrodistilled essential oil content of Origanum majorana L. (Lamiaceae) ranged from 2.5-3% with the maximal value (3%) in spring. Analysis of the oil by GC/MS resulted in the identification of 15, 15, 11, and 14 components in the oils prepared in spring, summer, autumn, and winter, respectively. The composition of the essential oils differed quantitatively and qualitatively according to the time of collection. Thymol (38.4%) and cis-sabinene hydrate (25.3%) were the major components in spring plants. Terpinen-4-ol (37.4%, 20.5%, 16.3%) was a major component in the summer, autumn and winter oils, respectively, cis-Sabinene hydrate (54.4%) was major in winter plants while terpinolene (43.1%) was the main component in autumn plants. Other components detected in lower amounts in all oil samples were sabinene and p-cymene (up to 7.4% and 13.9% in autumn), and alpha-terpinene (up to 13.3% in summer).

Flavonoids and biological activities of Jussiaea repens

A new acylated avicularin, namely avicularin 2''-(4'''-O-n-pentanoyl)-gallate (1) along with 12 metabolites have been isolated from the ethyl acetate extract of the aerial parts of Jussiaea repens L. (Onagraceae). Their structures were established as trifolin 2''-O-gallate (2), quercetrin (3), guaijaverin (4), reynoutrin (5), juglanin (6), avicularin (7), hyperin (8), trifolin (9), hyperin 2''-O-gallate (10), rutin (11), kaempferol (12) and quercetin (13) on the basis of their chromatographic properties, chemical and spectroscopic evidences. The investigated ethyl acetate extract was found to be non-toxic (LD(50) up to the maximum soluble dose 4 g kg(-1) body wt.) and had significant antioxidant, hepatoprotective, anti-inflammatory and antidiabetic activities. Also some of the isolated flavonoids showed cytotoxic activity against Ehrlich ascitis carcinoma cells.

Synthesis of some pyridone derivatives

Chlorination of 6-aryl-3-cyano-2-pyridone-4-carboxylic acid (1) afforded the corresponding acid chloride (2) and the 2-chloro derivative (3). Esterification of (2) gave the corresponding esters (4a; b). Hydrazinolysis of (4a) afforded the respective pyridazinone derivative (5). Treatment of 6-aryl-2-chloro-3-cyano-4-pyridine carboxylic acid (3) with acetyl hydrazine, gave the triazinopyridine derivative (6), while treatment of 3 with sodium azide in DMF afforded the tetrazinopyridine derivative (7). Treatment of the N-acetyl derivative (1b) with thiosemicarbazide and/or hydroxylamine hydrochloride, yielded the correspoding semicarbazone and oxine derivatives (8) and (10), respectively. The reaction of 6-aryl-3-cyano-1,2-dihydro-2-thioxo-4-pyridinecarboxylic acid (1c) with ethylchloro acetate and/or thiourea yielded the mercapto ester derivative (11) and the corresponding pyrido [2,3-d] pyrimidine thione derivative (12). Condensation reaction of (1d) with anthranilic acid, afforded the quinazolone derivative (11). The reactivity of 11 towards hydrazine hydrate was investigated. The structural assignment of the new derivatives were based on IR, 1H NMR and mass data. Some of the new compounds were screened, in vitro, for antimicrobial activity and the results were encouraging.

Induction of hsp70 by the herbicide oxyfluorfen (Goal) in the Egyptian Nile fish, Oreochromis niloticus

This paper deals with the expression of the biomarker hsp70 in the liver and kidney of the freshwater fish Oreochromis niloticus following exposure to the herbicide oxyfluorfen (Goal). Fishes were exposed to three concentrations, the 96-h LC50 (3 mg/L), the 96-h (1/2)LC50 (1.5 mg/L), and the 96-h (1/4)LC50 (0.75 mg/L) of oxyfluorfen for 6, 15, and 24 days, respectively, and samples were taken at three different time periods for each concentration. The livers responded to the herbicide by an induction of the expression of both the constitutive (hsp75; Mr 75 kDa) and the inducible (hsp73; Mr 73 kDa) hsp70 proteins. In kidney, the herbicide induced a time-dependent increase in the expression of the constitutive hsp70 (hsp75) as well, but the inducible hsp70 (hsp73) required much longer incubation periods to reach maximal levels (15 and 24 days). Our results suggest that expression of hsp70 in fish is a sensitive indicator of cellular responses to herbicide exposure in the aquatic environment.

Chemical composition and antimicrobial activity of essential oils of Jasonia candicans and J. montana

The essential oils of the aerial parts of Jasonia candicans and J. montana were analyzed by gas chromatography-mass spectrometry (GC/MS) technique. Of twenty-one components identified in the volatile oil of J. candicans, intermediol was the main constituent. Fifty-eight components were characterized in the essential oil of J. montana. Camphor, borneol, bornyl acetate, chrysanthemol, intermediol, and 1,8-cineole were the major constituents in this oil. The two oils showed antibacterial activity against Bacillus subtilis. They also showed a marked antifungal activity against Trichophyton mentagrophytes, Cryptococcus neoformans, and Candida albicans.

Organophosphorus compounds. XXII. The reaction of tertiary phosphonite, phosphinite and mixed phosphite esters with 2-Benzylideneindan-1,3-dione

Diethyl phenylphosphonite and ethyl diphenylphosphinite react with 2-benzylideneindan-1,3-dione(1) to give colourless addition compounds (6) and (8) respectively. The reaction of diethyl methyl phosphite and ethyl dimethyl phosphite with (1) leads to the formation of the corresponding phosphonates (9) and (11). Possible reaction mechanisms are considered and the structural assignments are based on chemical and spectroscopic evidence.