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Publications

Zhang, H.; Lin, S.; Xie, R.; Zhong, W.; Wang, H.; Farag, M. A.; Hussain, H.; Arroo, R. R.; Chen, X.; Xiao, J.; Thermal degradation of (2R, 3R)-dihydromyricetin in neutral aqueous solution at 100 ℃ Food Chem. 435, 137560, (2024) DOI: 10.1016/j.foodchem.2023.137560

In the field of thermal degradation of flavonoids, current studies mainly focused on flavonols. However, the thermal degradation of dihydroflavonols in aqueous solution has received limited attention compared to flavonols. The single C2-C3 bonds of dihydroflavonols, which differs from the C2-C3 double bond in flavonols, may cause different degradation mechanisms. Dihydromyricetin (DMY) is a typical dihydroflavonol with six hydroxyl groups, and possesses various health effects. We explored the thermal degradation of DMY in neutral aqueous solution (pH 7) at 100 ℃. Ultra-performance liquid chromatography combined with photodiode array and electrospray ionization quadrupole-time-of-flight tandem mass spectrometric detection (UPLC-PDA-ESI-QTOF-MS/MS) provided suitable platform for exploring DMY degradation pathways, and negative ion mode was applied. Thermal treatment led to a decline in DMY level with time, accompanied by the appearance of various degradation products of DMY. Degradation mechanisms of DMY included isomerization, oxidation, hydroxylation, dimerization and ring cleavage. The pyrogallol-type ring B of DMY might be initially oxidized into ortho-quinone, which could further attack another DMY to form dimers. In addition, hydroxylation is likely to occur at C-2, C-3 of DMY or DMY dimers, which then further yields ring-cleavage products via breakage of the O1-C2 bond, C2-C3 bond, or C3-C4 bond. The 3-hydroxy-5-(3,3,5,7-tetrahydroxy-4-oxochroman-2-yl) cyclohexa-3,5-diene-1, 2-dione (m/z 333.0244) and unknown compound m/z 435.0925 were annotated as key intermediates in DMY degradation. Four phenolic acids, including 3,4,5-trihydroxybenzoic acid (m/z 169.0136, RT 1.4 min), 2,4,6-trihydroxyphenylglyoxylic acid (m/z 197.0084, RT 1.7 min), 2-oxo-2-(2,4,6-trihydroxyphenyl) acetaldehyde (m/z 181.0132, RT 2.4 min), and 2,4,6-trihydroxybenzoic acid (m/z 169.0139, RT 2.5 min) were identified as the major end products of DMY degradation. In addition, 5-((3,5dihydroxyphenoxy) methyl)-3-hydroxycyclohexa-3,5-diene-1,2-dione (m/z 261.0399, RT 11.7 min) and unidentified compound with m/z 329.0507 (RT 1.0 min) were also suggested to be end products of DMY degradation. These results provide novel insights on DMY stability and degradation products. Moreover, the heat treatment of DMY aqueous solution was found to gradually reduce the antioxidant activities of DMY, and even destroy the beneficial effect of DMY on the gut microbiota composition.
Publications

Cheng, Y.; Zhao, H.; Cui, L.; Hussain, H.; Nadolnik, L.; Zhang, Z.; Zhao, Y.; Qin, X.; Li, J.; Park, J. H.; Wang, D.; Ultrasonic-assisted extraction of flavonoids from peanut leave and stem using deep eutectic solvents and its molecular mechanism Food Chem. 434, 137497, (2024) DOI: 10.1016/j.foodchem.2023.137497

Natural bioactive compounds extracted from agricultural by-products have received considerable attentions. Twenty-two kinds of deep eutectic solvents (DESs) with ultrasonic were screened to extract flavonoids from peanut leave and stem. ChCl-acetic acid (ChCl-Aa) with 1:2 M ratio resulted in more effective extraction of flavonoids compared to other solvents The best extraction conditions were found to be at a 27% water content in DES/H2O, for 43 min with 31:1 g/mL liquid/solid ratio, giving 2.980 mg/g dw of flavonoids through the response surface method. SEM showed that ChCl-Aa had a certain dissociation impact on the sample matrix, while 1H NMR analysis revealed the formation of hydrogen bonds between daidzein and ChCl-Aa. Changes in the H–bond length and number were observed by the B3LYP/6-31G (d,p) level of theory to confirm the experimental spectra. This study reveals that DESs are efficient for obtaining value-added products and could applied to other natural products.
Publications

Hussain, H.; How can we unlock the full potential of marine biological resources for novel drug discovery in an effective and ethical way? Expert Opinion on Drug Discovery 19, 125-130, (2024) DOI: 10.1080/17460441.2023.2285402

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Publications

Ning, F.; Zhu, H.; Yan, H.; Liu, J.; Aziz, S.; Hussain, H.; Song, X.; Xie, L.; Meng, Z.; Cao, G.; Wang, D.; Separation and purification of quinolyridine alkaloids from seeds of Thermopsis lanceolata R. Br. by conventional and pH‐zone‐refining counter‐current chromatography J Sep Sci 46, 2300053, (2023) DOI: 10.1002/jssc.202300053

In this work, the preparative separation of quinolyridine alkaloids from seeds of T. lanceolata by conventional and pH-zone-refining counter-current chromatography. Traditional counter-current chromatography separation was performed by a flow-rate changing strategy with a solvent system of ethyl acetate-n-butanol-water (1:9:10, v/v) and 200 mg sample loading. Meanwhile, the pH-zone-refining mode was adopted for separating 2.0 g crude alkaloid extracts with the chloroform-methanol-water (4:3:3, v/v) solvent system using the stationary and mobile phases of 40 mM hydrochloric acid and 10 mM triethylamine. Finally, six compounds, including N-formylcytisine (two conformers) (1), N-acetycytisine (two conformers) (2), (-)-cytisine (3), 13-β-hydroxylthermopsine (4), N-methylcytisine (5), and thermopsine (6) were successfully obtained in the two counter-current chromatography modes with the purities over 96.5%. Moreover, we adopted nuclear magnetic resonance and mass spectrometry for structural characterization. Based on the obtained findings, the pH-zone-refining mode was the efficient method to separate quinolyridine alkaloids relative to the traditional mode.
Publications

Lam, Y. T. H.; Hoppe, J.; Dang, Q. N.; Porzel, A.; Soboleva, A.; Brandt, W.; Rennert, R.; Hussain, H.; Davari, M. D.; Wessjohann, L.; Arnold, N.; Purpurascenines A–C, azepino-indole alkaloids from Cortinarius purpurascens: Isolation, biosynthesis, and activity studies on the 5-HT2A receptor J. Nat. Prod. 86, 1373-1384, (2023) DOI: 10.1021/acs.jnatprod.2c00716

Three previously undescribed azepino-indole alkaloids, named purpurascenines A−C (1−3), together with the new-to-nature 7-hydroxytryptophan (4) as well as two known compounds, adenosine (5) and riboflavin (6), were isolated from fruiting bodies of Cortinarius purpurascens Fr. (Cortinariaceae). The structures of 1−3 were elucidated based on spectroscopic analyses and ECD calculations. Furthermore, the biosynthesis of purpurascenine A (1) was investigated by in vivo experiments using 13C-labeled sodium pyruvate, alanine, and sodium acetate incubated with fruiting bodies of C. purpurascens. The incorporation of 13C into 1 was analyzed using 1D NMR and HRESIMS methods. With [3-13C]-pyruvate, a dramatic enrichment of 13C was observed, and hence a biosynthetic route via a direct Pictet−Spengler reaction between α-keto acids and 7-hydroxytryptophan (4) is suggested for the biosynthesis of purpurascenines A−C (1−3). Compound 1 exhibits no antiproliferative or cytotoxic effects against human prostate (PC-3), colorectal (HCT-116), and breast (MCF-7) cancer cells. An in silico docking study confirmed the hypothesis that purpurascenine A (1) could bind to the 5-HT2A serotonin receptor’s active site. A new functional 5-HT2A receptor activation assay showed no functional agonistic but some antagonistic effects of 1 against the 5-HT-dependent 5-HT2A activation and likely antagonistic effects on putative constitutive activity of the 5-HT2A receptor.
Publications

Jalil, K.; Ahmad, S.; Islam, N.; Ullah, R.; Jalil, Q.; Sulaiman, S.; Sajjad, A.; Ullah, R.; Alqahtani, A. S.; Bari, A.; Hussain, H.; Ali, E. A.; One pot synthesis, biological efficacy of AuNPs and Au-Amoxicillin conjugates functionalized with crude flavonoids extract of Micromeria biflora Molecules 28, 3320, (2023) DOI: 10.3390/molecules28083320

Amoxicillin is the most widely used antibiotic in human medicine for treating bacterial infections. However, in the present research, Micromeria biflora’s flavonoids extract mediated gold nanoparticles (AuNPs) were conjugated with amoxicillin (Au-amoxi) to study their efficacy against the inflammation and pain caused by bacterial infections. The formation of AuNPs and Au-amoxi conjugates were confirmed by UV–visible surface plasmon peaks at 535 nm and 545 nm, respectively. The scanning electron microscopy (SEM), zeta potential (ZP), and X-ray diffraction (XRD) studies reveal that the size of AuNPs and Au-amoxi are found to be 42 nm and 45 nm, respectively. Fourier-transform infrared spectroscopy (FT-IR) absorption bands at 3200 cm−1, 1000 cm−1, 1500 cm−1, and 1650 cm−1 reveal the possible involvement of different moieties for the formation of AuNPs and Au-amoxi. The pH studies show that AuNPs and Au-amoxi conjugates are stable at lower pH. The carrageenan-induced paw edema test, writhing test, and hot plate test were used to conduct in vivo anti-inflammatory and antinociceptive studies, respectively. According to in vivo anti-inflammatory activity, Au-amoxi compounds have higher efficiency (70%) after 3 h at a dose of 10 mg/kg body weight as compared to standard diclofenac (60%) at 20 mg/kg, amoxicillin (30%) at 100 mg/kg, and flavonoids extract (35%) at 100 mg/kg. Similarly, for antinociceptive activities, writhing test results show that Au-amoxi conjugates produced the same number of writhes (15) but at a lower dose (10 mg/kg) compared to standard diclofenac (20 mg/kg). The hot plate test results demonstrate that the Au-amoxi has a better latency time of 25 s at 10 mg/kg dose when compared to standard Tramadol of 22 s at 30 mg/ kg, amoxicillin of 14 s at 100 mg/kg, and extract of 14 s at 100 mg/kg after placing the mice on the hot plate for 30, 60, and 90 min with a significance of (p ≤ 0.001). These findings show that the conjugation of AuNPs with amoxicillin to form Au-amoxi can boost its anti-inflammatory and antinociceptive potential caused by bacterial infections.
Publications

Hussain, H.; Xiao, J.; Ali, A.; Green, I. R.; Westermann, B.; Unusually cyclized triterpenoids: occurrence, biosynthesis and chemical synthesis Nat. Prod. Rep. 40, 412-451, (2023) DOI: 10.1039/d2np00033d

Covering: 2009 to 2021Biosynthetically, most of the syntheses of triterpenes follow the cascade cyclization and rearrangement of the acyclic precursors viz., squalene (S) and 2,3-oxidosqualene (OS), which lead to the very well known tetra- and pentacyclic triterpene skeletons. Aside from these, numerous other triterpenoid molecules are also reported from various natural sources and their structures are derived from \"S\" and \"OS\" via some unusual cyclization operations which are different from the usual tetra- and pentacyclic frameworks. Numerous compelling advances have been made and reported in the identification of these unusual cyclized mono-, di-, tri- and tetracyclic triterpenes between 2009 and 2021. Besides a dramatic increase in the newly isolated uncommon cyclized triterpenoids, substantial progress in the (bio)-synthesis of these triterpenes has been published along with significant progress in their biological effects. In this review, 180 new unusual cyclized triterpenoids together with their demonstrated biogenetic pathways, syntheses and biological effects will be categorized and discussed.
Publications

Hussain, H.; Siddiqui, H.; Gerothanassis, I. P.; Prof. Dr. M. Iqbal Choudhary-A lifetime career dedicated to remarkable services in “natural products sciences” Frontiers in Pharmacology 14, 1119419, (2023) DOI: 10.3389/fphar.2023.1119419

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Publications

Hussain, A.; Attique, F.; Naqvi, S. A. R.; Ali, A.; Ibrahim, M.; Hussain, H.; Zafar, F.; Iqbal, R. S.; Ayub, M. A.; Assiri, M. A.; Imran, M.; Ullah, S.; Nanoformulation of Curcuma longa root extract and evaluation of its dissolution potential ACS Omega 8, 1088-1096, (2023) DOI: 10.1021/acsomega.2c06258

Medicinal plants have been widely used for therapeutic purposes for a long time, but they have been found to have some major issues such as low water solubility and bioavailability. In the present study, the nanoformulation of Curcuma longa L. plant extract was prepared to enhance its dissolution potential and biological activities. For the formulation of the nanosuspension, an ethanolic extract of C. longa was prepared through Soxhlet extraction using the nanoformulation technique. The nanosuspensions were formulated using four different stabilizers, namely sodium lauryl sulfate (SLS), hydroxy propyl methyl cellulose (HPMC), poly(vinyl alcohol) (PVA), and polysorbate-80 (P-80). The scanning electron microscopy (SEM), polydispersity index, and ζ potential were used for characterization of the nanoformulation. Among all of these, the surfactant stabilizer SLS was found to be the best. The average particle size of the selected optimized nanosuspension was found to be 308.2 nm with a polydispersity index (PDI) value of 0.330. The ζ potential value of the optimized nanosuspension was recorded at −33.3 mV. The SEM image indicated that the particles were slightly agglomerated, which may have occurred during lyophilization of the nanosuspension. The highest dissolution rate recorded at pH = 7 was 192.32 μg/mL, which indicates pH = 7 as the most appropriate condition for the dissolution of the C. longa nanosuspension. The antioxidant, antimicrobial, and antifungal activities of the optimized nanosuspension were also determined with regard to the coarse plant extract. The study findings suggested that the nanoprecipitation approach helps in enhancing the dissolution potential and biological activities of C. longa root extract.
Publications

Hussain, A.; Bourguet-Kondracki, M.-L.; Majeed, M.; Ibrahim, M.; Imran, M.; Yang, X.-W.; Ahmed, I.; Altaf, A. A.; Khalil, A. A.; Rauf, A.; Wilairatana, P.; Hemeg, H. A.; Ullah, R.; Green, I. R.; Ali, I.; Shah, S. T. A.; Hussain, H.; Marine life as a source for breast cancer treatment: A comprehensive review Biomedicine & Pharmacotherapy 159, 114165, (2023) DOI: 10.1016/j.biopha.2022.114165

Breast cancer, one of the most significant tumors among all cancer cells, still has deficiencies for effective treatment. Moreover, substitute treatments employing natural products as bioactive metabolites has been seriously considered. The source of bioactive metabolites are not only the most numerous but also represent the richest source. A unique source is from the oceans or marine species which demonstrated intriguing chemical and biological diversity which represents an astonishing reserve for discovering novel anticancer drugs. Notably, marine sponges produce the largest amount of diverse bioactive peptides, alkaloids, terpenoids, polyketides along with many secondary metabolites whose potential is mostly therapeutic. In this review, our main focus is on the marine derived secondary metabolites which demonstrated cytotoxic effects towards numerous breast cancer cells and have been isolated from the marine sources such as marine sponges, cyanobacteria, fungi, algae, tunicates, actinomycetes, ascidians, and other sources of marine organisms.
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