Sesquiterpene Derivatives Research Articles

Essential Oil Compositions and Antimicrobial Activities of Syzygium fluviatile (Hemsl.) Merr. & L.M.Perry: A Comparative Study on Collection Regions

Objective Essential oils extracted from Syzygium species are known for various pharmacological purposes. Syzygium fluviatile (Hemsl.) Merr. & L.M.Perry is a flowering plant found in China and Vietnam. The current study aims to offer a comparison of chemical compositions in essential oils of S. fluviatile fruits and leaves, collected from five regions of Vietnam. The obtained oils were also taken into antimicrobial consideration, which was further aided by in silico approaches. Methods Phytochemical analysis of essential oils was carried out using GC-FID/MS (gas chromatography-flame ionization detection/mass spectrometry) analysis. An antimicrobial assay was performed using broth micro-dilution for in vitro screening. In silico considerations are mainly based on docking studies and toxicity assessments using the AutoDock Vina v1.2.3 program and the ProTox 3.0 web server, respectively. Results Hydro-distillation of S. fluviatile fresh fruits and leaves can lead to the production of yellow essential oil with yields of 0.21–0.32% v/w. In general, the obtained oils were dominated by monoterpene and sesquiterpene derivatives, as well as ( E)-caryophyllene (8.40-47.12%) being the principal compound. The oil samples showed strong antimicrobial activity against the Gram (+) bacteria Enterococcus faecalis ATCC51299, Staphylococcus aureus ATCC29213, and Bacillus cereus ATCC11778, and the yeast Candida albicans ATCC 60193 with the MIC and IC50 values 16–64 µg/mL and 5.12–24.68 µg/mL. Docking results indicated that ( E)-caryophyllene exhibited binding affinities from −6.728 kcal/mol to −5.729 kcal/mol with important amino acid residues in the DNA gyrase, PBP3, and SAP2 targets. The toxicity profile of ( E)-caryophyllene is also discussed. Conclusion The isolation of ( E)-caryophyllene from Vietnamese Syzygium essential oils as a purified compound is necessary. In vivo antimicrobial studies and molecular mechanisms of action are needed.

Phenolic Bisabolane Sesquiterpene Derivatives from an Arctic Marine-derived Fungus Aspergillus sydowii MNP-2

Background:: Filamentous fungi in the genus Aspergillus are well known for their important roles in production of bioactive secondary metabolites with diversely chemical structures and potential application in pharmaceutical industry. Objective:: The present study aimed to investigate the phenolic bisabolane sesquiterpene (PBS) derivatives from an Arctic marine-derived fungus Aspergillus sydowii MNP-2. Methods:: In this study, antimicrobial activities were carried out according to the broth microdilution assay, nitric oxide (NO) production in mouse macrophages (RAW264.7) and BV2 microglial cells was used to detect the inhibitory effect of compounds in inflammatory reactions, and in vitro inhibitory cell proliferation activity was determined by the cell counting kit-8 (CCK-8) assay. Results:: In this work, chemical investigation of an Arctic marine-derived strain A. sydowii MNP-2 led to the isolation of 11 PBSs (1-11) using various chromatographic methods. Their chemical structures were unambiguously determined by 1H NMR spectroscopy and mass spectrometry analyses as well as comparison with literature data. It is noteworthy that compounds 1, 7 and 11 were firstly obtained from A. sydowii. Antimicrobial assay showed that these chemicals had no potent inhibitory effect on Staphylococcus aureus, Escherichia coli, and Candida albicans with MIC values > 16 μg/mL. Additionally, the inhibition of nitric oxide (NO) production in lipopolysaccharide (LPS)- induced inflammation in mouse macrophages (RAW264.7) and BV2 microglial cells were all below 10% for compounds 4-6 and 8, indicating almost negligible anti-inflammatory efficacy. Among the tested compounds 4-6 and 8 for tumor-cell proliferation inhibition activities, compound 5 demonstrated the strongest inhibitory effect against human acute promyelocytic leukemia cells (HL-6) with a 44.76% inhibition rate. Conclusion:: In the present study, 11 PBS derivatives were purified and characterized from the solidand liquid-state fermentations of the Arctic marine-derived fungus A. sydowii MNP-2. Unfortunately, none of these metabolites had significant antimicrobial, anti-inflammatory, or tumor-cell proliferation inhibition activities.

Targeted isolation of dimeric sesquiterpene lactones and sesquiterpene derivatives from the roots of Inula helenium

LC-HRMS/MS-based molecular networking was applied to investigate the bioactive sesquiterpene lactones and their analogs contained in Inula helenium, enabling the isolation of four undescribed eudesmane-eudesmane sesquiterpene dimers (1–4), a sesquiterpene-amino acid adduct (5), and 17 known sesquiterpenes (6–22). The structures were determined based on 1D, 2D NMR, and HRESIMS data analysis, as well as DP4+ probability analyses and ECD calculations. The biosynthetic pathway of the sesquiterpene dimers is postulated to proceed via the Diels-Alder reaction as the key step. The inhibitory activity of all isolates on LPS-induced nitric oxide (NO) production in RAW 264.7 macrophages was evaluated. Compounds 4, 17, and 20 exhibited significant inhibitory activity against NO production, with IC50 values of 8.4, 5.5, and 9.1 μM, respectively.

Essential Oils of Two Species of Zingiberaceae Family from Vietnam: Chemical Compositions and α-Glucosidase, α-Amylase Inhibitory Effects

The ginger family (Zingiberaceae) is one of the most diverse and abundant families in the plant kingdom in terms of number of species. In terms of chemistry, this is a family of plants containing much essential oil with mainly monoterpene and sesquiterpene derivatives, which has been widely used in medicine, food, and flavor industries. In our series of studies on ginger family plants, the two new species including Wurfbainia schmidtii (K. Schum.) Škorničk. & A.D. Poulsen and Zingiber atroporphyreus Škorničk. & Q.B. Nguyen has been investigated for the first time. This study aimed to identify the chemical compositions of essential oils extracted from the rhizomes and leaves of these two species using gas chromatography-mass spectrometry (GC/MS) analysis and evaluate their hypoglycemic effects through the α-glucosidase and α-amylase inhibitory assays. In terms of chemical composition, in general, the main compounds appearing in the essential oils of both leaves and rhizomes of each species are similar but they are differences in the percentage of the main components, for example, 1,8-cineole is a main component in leaves whereas fenchyl acetate is the main one in rhizomes of W. schmidtii. Several distinctive compounds, in comparison with other members in the genus Zingiber, namely β-pinene, α-pinene, β-elemene, and sabinene, were found in the essential oil of Z. atroporphyreus. Regarding hypoglycemic effects, the essential oils from the two species tested possessed weak α-glucosidase and α-amylase inhibitory effects. For the first time, this study was designed to investigate the chemical composition as well as the hypoglycemic effect of essential oils distilled from the rhizomes and leaves of two species W. schmidtii and Z. atroporphyreus have been reported, serving as a premise for further systematic research on their phytochemistry and pharmacological effects being conducted.

Sesquiterpenes from Wikstroemia lungtzeensis with anti-neuroinflammatory effects

An anti-neuroinflammatory activities-guided phytochemical research of Wikstroemia lungtzeensis was performed for the first time. Three undescribed carotane-type sesquiterpenes, excoecafolinols C-E (1–3), and nine known sesquiterpene derivatives were isolated from the effective ethyl acetate extract of W. lungtzeensis. Their structures were determined based on multiple spectroscopic techniques and electronic circular dichroism (ECD) spectra. Furthermore, the anti-neuroinflammatory activities of the identified compounds were evaluated in lipopolysaccharide-stimulated BV-2 cells. Among them, six components (1, 2, 4, 7, 11, 12) exhibited significant inhibitory effects on nitric oxide (NO) production, with IC50 values ranging from 10.48 to 49.41 μM (positive control minocycline, IC50 53.20 μM). Carotane-type sesquiterpenes (1, 2, 4) with high content and significant inhibitory effects, are considered to be major active ingredients of W. lungtzeensis, which might serve as potential therapeutic agents for neurodegenerative diseases.

Effectiveness of sesquiterpene derivatives from Cinnamomum genus in nicotine replacement therapy through blocking acetylcholine nicotinate: a computational analysis

Cigarette smoking poses various health risks, such as increasing the susceptibility to respiratory infections, contributing to osteoporosis, causing reproductive issues, delaying postoperative recovery, promoting ulcer formation and heightening the risk of diabetes. While many harmful effects of smoking are attributed to other cigarette components, it is nicotine’s pharmacological effects that underlie tobacco addiction. Nicotine replacement therapy (NRT) aims to alleviate the urge to smoke and mitigate physiological and psychomotor withdrawal symptoms by delivering nicotine. This study explores the potential of sesquiterpene derivative compounds derived from the Cinnamomum genus using computational techniques. The research incorporates molecular docking analyses, Lipinski’s rule of five filtration for drug-likeness, pharmacokinetic and toxicity predictions to assess safety profiles and molecular dynamics (MD) simulations to gauge interaction stability. The findings reveal that all sesquiterpene derivative compounds from the Cinnamomum genus can potentially inhibit nicotinic acetylcholine receptors (nAChRs), particularly nAChRÿ7. However, only abscisic acid exhibit active inhibition, along with suitable drug properties, pharmacokinetics and toxicity profiles. MD studies confirm the stability of interactions between abscisic acid with nAChRÿ7. Consequently, abscisic acid, as sesquiterpene derivatives from the Cinnamomum genus, holds substantial promise for further investigation as nAChRÿ7 inhibitors. Communicated by Ramaswamy H. Sarma

Anti-Agrobacterium tumefactions sesquiterpene derivatives from the marine-derived fungus Trichoderma effusum.

Agrobacterium tumefaciens can harm various fruit trees, leading to significant economic losses in agricultural production. It is urgent to develop new pesticides to effectively treat this bacterial disease. In this study, four new sesquiterpene derivatives, trichoderenes A-D (1-4), along with six known compounds (5-10), were obtained from the marine-derived fungus Trichoderma effusum. The structures of 1-4 were elucidated by extensive spectroscopic analyses, and the calculated ECD, ORD, and NMR methods. Structurally, the hydrogen bond formed between the 1-OH group and the methoxy group enabled 1 to adopt a structure resembling that of resorcylic acid lactones, thereby producing the ECD cotton effect. Compound 3 represents the first example of C12 nor-sesquiterpene skeleton. Compounds 1-10 were tested for their antimicrobial activity against A. tumefactions. Among them, compounds 1-3 and 8-10 exhibited inhibitory activity against A. tumefactions with MIC values of 3.1, 12.5, 12.5, 6.2, 25.0, and 12.5 μg/mL, respectively.

Salvirrane A-F, six undescribed nordrimane sesquiterpene derivatives from Salvia castanea Diels f. tomentosa Stib and their cytotoxic activities

Six undescribed nordrimane sesquiterpene derivatives, salvirrane A-F (1–6), were isolated from the roots and rhizomes of Salvia castanea Diels f. tomentosa Stib. Comprehensive spectral analysis and a quantum chemical calculation strategy were employed to determine their structures. These compounds represent four previously unreported nordrimane carbon skeletal types in Salvia genus, including 15-nor-drimane, 11,15-di-nor-drimane, 14,15-di-nor-drimane, and 11,14,15-tri-nor-drimane sesquiterpenes. All compounds were evaluated for their cytotoxic activities against several human cancer cell lines (A549, H460, Hep3B, MCF7, PC3, and HeLa). The results showed that 3 exhibited low activity against MCF7 cells (IC50,72.72 ± 6.95 μM) and moderate activity against HeLa cells (IC50, 9.80 ± 0.64 μM). Moreover, the EdU (5-ethynyl-2′-deoxyuridine) assay demonstrates that 3 displays dose-dependent efficacy in suppressing the proliferation of HeLa cells. Network pharmacology and molecular docking technology implied that 3 may potentially bind to Src (proto-oncogene tyrosine-protein kinase) to exert anti-proliferative activity.

Recording insect death and essential oil composition of Ferula communis L. flowers in Al Ula, Kingdom of Saudi Arabia

Natural bioactive compounds, which occur in aromatic plants, are now more widely recognized. The aromatic plant family Apiaceae, which has various bioactivities and chemical compositions, includes Ferula communis L. The authors planned frequent field expeditions to two locations where Ferula communis L. grows, Hassat Al-Dab and Almotadal, which are close to the Al Ula Government in the Kingdom of Saudi Arabia. The flowers of Ferula communis L. were cut and dried for hydrodistillation using a Clevenger-type apparatus. During the flowering season of Ferula communis L., some insects were found dead on the flowers; Simosyrphus aegyptius, Colletes latreille, and Apis mellifera. GC-MS techniques were used to analyze the essential oils (Eos) of the Ferula communis L. flower obtained by hydrodistillation. Forty-two compounds were identified in the total essential oils. Oxygenated and hydrocarbon sesquiterpenes were the most dominant class of compounds in the flower oils. The main representatives of these groups were dihydrodehydrocostus lactone (15.0%), α-acorenol (8.4%), α-eudesmol (7.1%), eudesma-4, 11-dien-2-ol (5.3%), elemol (4.9%), aristolene (4%), γ-elemene (3.8%), epi-cedrol (3.5), and β-eudesmol (3.4%), respectively, as the most abundant components. Besides the sesquiterpene derivatives, an active constituent oxygenated monoterpene was obtained from the essential oil and identified as 4-(3,3-dimethyl-but-1-ynyl)-4-hydroxy-2,6,6-trimethylcyclohex-2-enone (4.6%). The study concluded that the flowers of Ferula communis L. and its essential oil would be good candidates as biopesticides.

Sesquiterpenes and Sesquiterpene Derivatives from Ferula: Their Chemical Structures, Biosynthetic Pathways, and Biological Properties.

Ferula is a genus of flowering plants known for its edible and medicinal properties. Since ancient times, many species of Ferula have been used in traditional medicine to treat various health issues across countries, such as digestive disorders, respiratory problems, and even as a remedy for headaches and toothaches. In addition, they are also used as a flavoring agent in various cuisines. As the main active ingredients in Ferula, sesquiterpenes and their derivatives, especially sesquiterpene coumarins, sesquiterpene phenylpropanoids, and sesquiterpene chromones, have attracted the attention of scientists due to the diversity of their chemical structures, as well as their extensive and promising biological properties, such as antioxidative, anti-inflammatory, antibacterial properties. However, there has not been a comprehensive review of sesquiterpenes and their derivatives from this plant. This review aims to provide an overview of the chemical structures, biosynthetic pathways, and biological properties of sesquiterpenes and sesquiterpene derivatives from Ferula, which may help guide future research directions and possible application methods for this valuable edible and medicinal plant.

Pseudoceranoids A-J, Sesquiterpene-Based Meroterpenoids with Cytotoxicity from the Sponge Pseudoceratina purpurea.

Pseudoceranoid A (1), a rare merosesquiterpene featuring a rearranged 4,9-friedodrimane-type core with a crotonolactone moiety, two new rearranged 4,9-friedodrimane-type sesquiterpene cyclopentanones (2 and 3), and three new rearranged 4,9-friedodrimane-type sesquiterpene hydroquinones (4-6), along with two new drimane-type sesquiterpene derivatives (7 and 8), as well as two new 4,9-friedodrimane-type sesquiterpene quinones (9 and 10), were isolated from the South China Sea sponge Pseudoceratina purpurea. The structures of compounds were established by analysis of spectroscopic data, as well as by single-crystal X-ray diffraction, DP4+ probability analyses, and calculated electronic circular dichroism. Compound 4 showed weak cytotoxicity against K562, H69AR, and MDAMB-231 cell lines with IC50 values of 3.01, 7.74, and 9.82 μM, respectively. Compound 5 exhibited cytotoxicity against the H69AR cell line with an IC50 value of 2.85 μM.

Tapirira guianensis is Selectively Cytotoxic, Induces Apoptosis to the Glioblastoma and Decreases Tumor Growth and Angiogenesis in vivo.

Glioblastoma is the most frequent primary malignant brain tumor without effective treatment, which makes this work extremely relevant. The study of the bioactive compounds from medicinal plants plays an important role in the discovery of new drugs.This research investigated the constituents of Tapirira guianensis and its antitumor potential (in vitro and in vivo) in glioblastoma. The T. guianensis extracts were characterized by mass spectrometry. The ethyl acetate partition (01ID) and its fractions 01ID-F2 and 01ID-F4 from T. guianensis showed potential antitumor treatment evidenced by selective cytotoxicity for GAMG with IC50 14.1 µg/mL, 83.07 µg/mL, 59.27 µg/mL and U251 with IC50 25.92 µg/mL, 37.3 µg/mL and 18.84 µg/mL. Fractions 01ID-F2 and 01ID-F4 were 10 times more selective when compared to TMZ and 01ID for the two evaluated cell lines. T. guianensis also reduced matrix metalloproteinases 2 - 01ID-F2 (21.84%), 01ID-F4 (29.6%) and 9 - 01ID-F4 (73.42%), ID-F4 (53.84%) activities, and induced apoptosis mainly through the extrinsic pathway. Furthermore, all treatments significantly reduced tumor size (01ID p < 0,01, 01ID-F2 p < 0,01 and 01ID-F4 p < 0,0001) and caused blood vessels to shrink in vivo. The present findings highlight that T. guianensis exhibits considerable antitumor potential in preclinical studies of glioblastoma. This ability may be related to the phenolic compounds and sesquiterpene derivatives identified in the extracts. This study deserves further in vivo research, followed by clinical investigation.

Research progress on chemical constituents and pharmacological activities of halogenated sesquiterpenes from natural sources

Halogenated sesquiterpenes are important derivatives of sesquiterpenes, referring to chemical components of sesquiterpenes that contain halogens such as chlorine, bromine, and iodine. Halogenated sesquiterpenes have attracted attention from researchers in China and abroad because of their diverse structures, unique halogen elements, and extensive pharmacological activities. Studies have shown that halogenated sesquiterpenes exhibit significant antimicrobial, anti-inflammatory, anticancer, insecticidal, hypoglycemic, and enzyme inhibitory activities. In order to better explore the potential pharmaceutical value of halogenated sesquiterpenes, this paper reviewed the structural characteristics and pharmacological activities of halogenated sesquiterpenes in the past two decades, aiming to provide references for further research and development of this class of compounds.

Acid-catalyzed rearrangement of biomass polycyclic sesquiterpene derivatives to high-performance alkyl-adamantanes

Biomass-based aviation fuel is attractive for sustainable development. Herein, we report a facile route to synthesize alkyl-adamantanes (AAMs) via acid-catalyzed rearrangement of biomass polycyclic sesquiterpene derivatives (bio-PCS derivatives). The reaction conditions including catalysts, solvents, reaction temperature and reaction time were optimized. Notably, a total AAMs yield of 65.1% was achieved under the optimal conditions. The kinetics of rearrangement reaction was investigated, and the reaction rate constant (k) and apparent activation energy (Ea) were calculated based on the experimental kinetic data. The rearrangement products possess high density of 0.90 g/cm3, high net heat of combustion of 42.6 MJ/kg, low viscosity (22.5 mm2/s at −20℃) and high thermal oxidative stability. The blending of rearrangement products with JP-10 can significantly shorten the ignition delay time (IDT) of JP-10. This work provides a method to synthesize high-performance biomass-based AAMs.

New antiprotozoal sesquiterpene derivatives from Dorema glabrum Fisch & C.A.Mey

Seven undescribed sesquiterpene derivatives, Azerins A-G (3–6, 8, 14 and 15), three known sesquiterpene phenols, kopetdaghin A (1), kopetdaghin B (2) and latisectin (7), together with five known sesquiterpene coumarins (9–13), were isolated from the roots of Dorema glabrum. The structures were elucidated by comprehensive 1D- and 2D-NMR spectral analysis as well as HR-ESI-MS. Compounds were assessed for their in vitro antiprotozoal activity against Trypanosoma brucei rhodesiense, T. cruzi, Leishmania donovani, and Plasmodium falciparum. Cytotoxic potentials of the compounds were also tested on L6 rat skeletal myoblasts. Azerin G (15) showed a potent preferential growth inhibitory activity against T. b. rhodesiense with IC50 value of 0.01 μM and selectivity index of 329. Compounds 1, 4, 7 and 8 were also found as the most active compounds with selective growth inhibitory effects toward P. falciparum with selectivity indices ranging from 11.6 to 16.7 (IC50: 1.8–24.6 μM).

Acetylcholinesterase inhibitory activity of Ferula plants and their potential for treatment of Alzheimer's disease.

One of the current strategies in the treatment of Alzheimer's disease is using drugs with acetylcholinesterase (AChE) inhibitory property. The existence of various compounds in plants as a potential source for finding new compounds to treat Alzheimer's disease is a scientific fact. Many secondary metabolites and plant extracts have been reported with the ability to inhibit the AChE activity and improve memory and learning. These compounds can increase the concentration of acetylcholine in the brain and improve cholinergic function in individuals with Alzheimer's disease and reduce the symptoms of this neurological disorder. Plants of Ferula genus are a good source ofbiologically active compounds such as sesquiterpene derivatives, coumarin derivatives and sulfur-containing compounds. Numerous studies on various extracts or purified compounds of Ferula genus have shown that members of this genus have the inhibitory properties on acetylcholinesterase and can also be effective in improving Alzheimer's and amnesia. This review article summarizes studies on plants of Ferula extracts and their derived compounds to find AChE inhibitors.

Derivatives of sesquiterpenes, 2-furaldehyde, phenols, and alkaloids isolated from Taraxacum mongolicum

Four new compounds (1–4), together with 23 known compounds (5–27), were isolated from the whole plant of Taraxacum mongolicum. Among them, one racemic mixture (4) was separated with a chiral HPLC column. Their structures were identified by spectroscopic evidence and mass spectrometry. The absolute configurations of compounds 1, 3, and 4 were determined via comparison of their calculated and experimental electronic circular dichroism (ECD) spectra. Compound 3 showed an inhibitory effect against aldose reductase with a 59.1% inhibition. Two known compounds (13 and 27) showed α-glucosidase inhibition of 51.5% and 56.0%, respectively.

Bioactive principles, antibacterial and anticancer properties of Artemisia arborescens L.

Artemisia arborescens is a medicinal and aromatic plant used in traditionally by the people of Saudi Arabia. This research attempts to evaluate the bioactive constituents of the plant using organic solvents, as well as the antibacterial and anticancer properties of plant extracts. The Phytochemical analysis of methanol extract revealed eleven bioactive constituents, identified by comparing their retention periods and GC-MS profiles to account for 52.45 percent of the studied extract. In the meantime, the extract of pet ether had demonstrated the presence of sixteen significant constituents, six of which were distinct sesquiterpene derivatives. In lipophilic plant extract, three higher alkanes made up 12.49% of the total. These higher alkanes were tetratriacontane (6.55%), hentriacontane (4.17%), and octacosane (1.77%). Studies on antimicrobial activity have revealed that both methanolic and petroleum ether extracts had a broad spectrum of activity against specific human pathogens. Both extracts, however, failed to exhibit any anti-Candida albicans activity. Methanolic extract not shown inhibition in the cell growth of MCF-7 cell, but petroleum ether extract had shown significant anti-cancer activity against MCF-7 cell with an IC50 of 13.49 µg/mL. the results obtained show that A. arborescens have a lot of potential for further research into variety of biological functions, against cancer and microbes.

Two new sesquiterpene derivatives, dendocarbin B and bisaborosaol C with antifungal activity from the endophytic fungus Nigrospora chinensis GGY-3

Two novel sesquiterpene derivatives, dendocarbin B (1), bisaborosaol C (2), and nine known compounds (3-11), were isolated from Nigrospora chinensis GGY-3 derived from Ilex cornuta. The structures of new compounds were elucidated using HR-ESI-MS, 1 D and 2 D NMR spectra, X-ray diffraction analysis as well as ECD calculation and comparison. Compound 1 showed moderate antifungal activities against Rhizoctonia solani and Botrytis cinerea. Compounds 5 and 6 exhibited significant inhibitory activity against Phytophthora capsici, Magnaporthe oryzae and R. solani with EC50 values ranging from 13.91 to 29.49 μg/mL. Compounds 10 and 11 displayed moderate antibacterial effects on Bacillus subtilis and Xanthomonas oryzae pv. oryzae (Xoo), with MIC values of 16-64 μg/mL. Particularly, 11 presented strong antibacterial activity against Staphylococcus aureus with an MIC value of 4 μg/mL (2 μg/mL for streptomycin sulfate). In addition, compound 11 also possessed DPPH radical scavenging capability with an IC50 value of 14.80 μg/mL.

A simple synthesis of α-Costic acid analogue with antibacterial potential, DFT and molecular docking

Natural products extracted from plants has been recognized as the most efficient starting materials to synthesize new derivatives of medicinal interest. Our research focuses on the isolation and characterization of sesquiterpene derivatives from Dittrichia Viscosa (L), as well as their hemisynthesis. To that end, a phytochemical study of Dittrichia viscosa leaves was conducted in order to obtain a sesquiterpenoid, α -Costic acid, which will be further transformed to γ -Costic acid with high yield using simple processes. Optimized molecular geometry and vibrational frequencies of both products were computed using the density functional theory. In addition, the antibacterial activity of isolated and hemisynthesized products were analyzed in vitro against Escherichia coli resistant to β-lactamase 616, Pseudomonas aeruginosa, and Staphylococcus aureus. The obtained compounds were investigated by in silico biological method to evaluate their potential inhibitory activity against same strains using FtsA, LasR proteins and DNA polymerase III enzyme.