A new diterpenoid from Salvia santolinifolia boiss

Phytochemical study of the Salvia santolinifolia root extract resulted in the isolation of one new quinone diterpenoid, aegyptinone E (1) as well as two known ones, aegyptinone A (2) and aegyptinone D (3). All the isolated compounds were reported for the first time from S. santolinifolia. Spectroscopic analyses including 1 D and 2 D NMR and HRESIMS were used to determine the chemical structures. Aegyptinone A (2) showed moderate antibacterial activity against Staphylococcus aureus, Staphylococcus epidermis, and Bacillus subtilis with MIC of 25 μg/mL.

C19-diterpene alkaloids from delphinium turkmenum lipsky

The genus Delphinium is a rich source of diterpene alkaloids. Chemical investigation on an alkaloid rich extract of the whole parts of Delphinium turkmenum resulted in the isolation of three C19-diterpene alkaloids (1-3) and a palmitic acid derivative (4). The chemical structures were elucidated by analysis of 1D and 2D-NMR and comparison the data with those reported in the literature. Notably, all isolated compounds were reported for the first time from D. turkmenum.

In vitro antimicrobial and antibiofilm screening of eighteen Iranian medicinal plants

BACKGROUND

Natural products are one of the best candidates for controlling drug-resistant pathogens, the advantages of which include low production costs and low side effects. In this study, as potential antimicrobials, the anti-bacterial and antibiofilm activities of several Iranian native medicinal plants were screened.

METHODS

The antibacterial/antifungal and anti-biofilm activities of 18 medicinal plants including Reseda lutea L., Nepeta sintenisii Bunge., Stachys turcomanica Trautv., Stachys lavandulifolia Vahl, Diarthron antoninae (Pobed.) Kit Tan., Ziziphora clinopodioides Lam., Euphorbia kopetdaghi Prokh, Euphorbia serpens Kunth., Hymenocrater calycinus Benth., Scutellaria pinnatifida A.Ham., Viola tricolor L., Hypericum helianthemoides (Spach) Boiss., Hypericum scabrum L., Convolvulus lineatus L., Scabiosa rotata M.Bieb Greuter & Burdet, Delphinium semibarbatum Bien. Ex Boiss., Glycyrrhiza triphylla Fisch. & C.A.Mey., and Ziziphus jujuba Mill., against two Gram-positive bacteria, Staphylococcus aureus, Bacillus cereus, as well as two Gram-negative bacteria, Pseudomonas aeruginosa, Escherichia coli; and Candida albicans as a fungal strain, were evaluated. The minimum inhibitory concentration (MIC) and minimum bactericidal/fungicidal concentration (MBC/MFC) values of the extracts against tested microorganisms were reported and we investigated their effect on the biofilm inhibition of Pseudomonas aeruginosa PAO1, Staphylococcus epidermis, Staphylococcus aureus and Streptococcus mutans. In addition, the effect of the extracts on the eradication of the biofilms of these bacteria was evaluated.

RESULTS

In this study, H. scabrum was found to exhibit potentially significant activity against Gram-positive bacteria with the MIC range of 6.25-25 µg/mL. This extract also showed a significant effect on inhibiting the biofilm of S. aureus, S. mutans, and S. epidermidis and eradicating the biofilm of S. epidermidis DSMZ 3270. In addition, Hymenocrater calycinus root extract had moderate antibacterial activity against B. cereus with the MIC and MBC 62.5 µg/mL, respectively.

CONCLUSIONS

The results of this study showed that the root extracts of two plants, Hypericum scabrum and Hymenocrater calycinus, had antimicrobial and anti-biofilm effects. Based on the observed anti-biofilm effects, these two plants may be considered in future studies to find responsible antimicrobial compounds.

Diverse diterpenoids and a triterpenoid from Euphorbia spinidens Bornm. ex Prokh

Four previously unreported diterpenoids including three ent-atisanes (1-3) and one ent-abietane (4), along with one known linear triterpenoid (5) and five known diterpenoids including four myrsinanes (6-9), and one abietane (10) have been isolated from the roots of Euphorbia spinidens Bornm. ex Prokh. The structures were determined on the basis of extensive spectroscopic analyses including HR-ESI-MS, 1D and 2D NMR and comparison of the data with those reported in the literature. Antimicrobial potential of isolated compounds were also evaluated. Guionianol B (10) showed good antibacterial activity against Staphylococcus aureus and Bacillus subtilis with MIC value of 6.25 μg/mL.

Antimicrobial and cytotoxic naphthoquinones from microbial origin: An updated review

Naphthoquinones (NQs) are small molecules bearing two carbonyl groups. They have been the subject of much research due to their significant biological activities such as antiproliferative, antimicrobial, anti-inflammatory, antioxidant, and antimalarial effects. NQs are produced mainly by bacteria, fungi and higher plants. Among them, microorganisms are a treasure of NQs with diverse skeletons and pharmacological properties. The purpose of the present study is to provide a comprehensive update on the structural diversity and biological activities of 91 microbial naphthoquinones isolated from 2015 to 2022, with a special focus on antimicrobial and cytotoxic activities. During this period, potent cytotoxic NQs such as naphthablin B (46) and hygrocin C (30) against HeLa (IC50=0.23 µg/ml) and MDA-MB-431 (IC50=0.5 µg/ml) cell lines was reported, respectively. In addition, rubromycin CA1 (39), exhibited strong antibacterial activity against Staphylococcus aureus (MIC of 0.2 µg/ml). As importance bioactive compounds, NQs may open new horizon for treatment of cancer and drug resistant bacteria. As such, it is hoped that this review article may stimulates further research into the isolation of further NQs from microbial, and other sources as well as the screening of such compounds for biological activity and beneficial uses.

The Regulation, Functions, and Signaling of miR-153 in Neurological Disorders, and Its Potential as a Biomarker and Therapeutic Target

Treatment of neurological disorders has always been one of the challenges facing scientists due to poor prognosis and symptom overlap, as well as the progress of the disease process. Neurological disorders such as Huntington's, Parkinson's, Alzheimer's diseases, and Amyotrophic Lateral Sclerosis are very debilitating. Therefore, finding a biomarker is essential for early diagnosis and treatment goals. Recent studies have focused more on molecular factors and gene manipulation to find effective diagnostic and therapeutic biomarkers. Among these factors, microRNAs (miRNAs/ miRs) have attracted much attention. On the other hand, a growing correlation between miRNAs and neurological disorders has caused scientists to consider it as a diagnostic and therapeutic target. In this line, the miR-153 is one of the most important and highly conserved miRNAs in mice and humans, whose expression level is not only altered in neurological disorders but also improves neurogenesis. MiR-153 can regulate multiple biological processes by targeting various factors. Furthermore, the miR-153 expression also can be regulated by important regulators, such as long non-coding RNAs (e.g., KCNQ1OT1) and some compounds (e.g., Tanshinone IIA) altering the expression of miR-153. Given the growing interest in miR-153 as a biomarker and therapeutic target for neurological diseases as well as the lack of comprehensive investigation of miR-153 function in these disorders, it is necessary to identify the downstream and upstream targets and also it's potential as a therapeutic biomarker target. In this review, we will discuss the critical role of miR-153 in neurological disorders for novel diagnostic and prognostic purposes and its role in multi-drug resistance.

Neuroprotective Effects of Sesamum indicum, Sesamin and Sesamolin Against 6-OHDA-induced Apoptosis in PC12 Cells

BACKGROUND

Sesamum indicum L. (sesame) is one of the most widely used herbs in the world. Sesame oil contains lignans such as sesamin and sesamolin, which are known to possess anti-inflammatory, antioxidant, and anti-apoptotic properties. Parkinson's disease (PD) is recognized as the most common neurodegenerative disease after Alzheimer's disease; however, the exact molecular mechanism of the progression of neural death is not clear yet. In this study, the effect of sesame seed extracts and their main bioactive components (sesamin and sesamolin) on in vitro model of Parkinson's disease has been compared.

METHODS

Cell viability, the number of reactive oxygen species (ROS), and apoptosis were determined using resazurin assay, ROS assay, propidium iodide (PI) staining and flow cytometry, and western blot analysis.

RESULTS

6-OHDA caused cellular death and apoptosis but pretreatment with sesame seed extracts, sesamin, and sesamolin significantly increased cell viability (p<0.001) and decreased ROS (p<0.001) and apoptosis. ERK1/2 is activated by 6-OHDA in PC12 cells, and the level of survivin decreased. Pretreatment with sesame significantly reversed the entire cell death induced by 6- OHDA. Sesame seed extracts at 5 and 10 μg/ml, sesamin and sesamolin at 5 and 10 μM increased surviving (p<0.01), and reduced P-ERK1/2/ERK1/2 (p<0.05) levels close to the control values.

CONCLUSIONS

Overall, compounds in sesame seed extract and sesamin may assist as adjuvant therapeutics in PD. It seems sesame seeds have more potent protection effects against neural death compared with individual components, which might reflect the synergism among different phytochemicals present in the extract.

Efficacy of orally administered montmorillonite in myoglobinuric acute renal failure model in male rats

Objectives

Acute kidney injury can be associated with serious consequences and therefore early treatment is critical to decreasing mortality and morbidity rate. We evaluated the effect of montmorillonite, the clay with strong cation exchange capacity, on the AKI model in rats.

Materials and Methods

Glycerol (50% solution, 10 ml/kg) was injected in the rat hind limbs to induce AKI. 24 hr after induction of acute kidney injury, the rats received oral doses of montmorillonite (0.5 g/kg or 1 g/kg), or sodium polystyrene sulfonate (1 g/kg) for three consecutive days.

Results

Glycine induced acute kidney injury in rats with high levels of urea (336.60± 28.19 mg/dl), creatinine (4.10± 0.21 mg/dl), potassium (6.15 ± 0.28 mEq/L), and calcium (11.52 ± 0.19 mg/dl). Both doses of montmorillonite (0.5 and 1 g/kg) improved the serum urea (222.66± 10.02 and 170.20±8.06, P<0.05), creatinine (1.86±0.1, 2.05± 0.11, P<0.05), potassium (4.68 ± 0.4, 4.73 ± 0.34, P<0.001) and calcium (11.15 ± 0.17, 10.75 ± 0.25, P<0.01) levels. Treatment with montmorillonite especially at a high dose reduced the kidney pathological findings including, tubular necrosis, amorphous protein aggregation, and cell shedding into the distal and proximal tubule lumen. However, administration of SPS could not significantly decrease the severity of damages.

Conclusion

According to the results of this study, as well as the physicochemical properties of montmorillonite, such as high ion exchange capacity and low side effects, montmorillonite can be a low-cost and effective treatment option to reduce and improve the complications of acute kidney injury. However, the efficacy of this compound in human and clinical studies needs to be investigated.

LC-MS-based metabolite profiling of aqueous extract of Pergularia tomentosa L. and its anti-hyperglycemic effect

Objectives

In this study, to find scientific evidence for the traditional use of Pergularia tomentosa as an anti-diabetic remedy, the effects of its aqueous extract on streptozotocin-induced diabetes mellitus in rats were evaluated.

Materials and Methods

Wistar rats were fasted overnight and diabetes mellitus was induced using streptozotocin (50 mg/kg body weight). The rats were randomly and equally divided into four groups (n=5): group I (normoglycaemic control), group II (diabetic rats), group III (diabetic rats treated with 200 mg/kg BW of an aqueous extract of P. tomentosa), group IV (normoglycemic rats treated with 200 mg/kg BW of an aqueous extract of P. tomentosa). Chemical profiling of the aqueous extract was carried out using liquid chromatography coupled with electrospray ionization and multiple-stage linear ion-trap and orbitrap high-resolution mass spectrometry (LC-ESI/LTQOrbitrap/MS/MS). In addition, the quantitative determination of the main cardenolides in the extract was carried out by an analytical approach based on LC coupled to tandem mass spectrometry with ESI source and hybrid triple quadrupole-linear ion trap mass analyzer (LC-ESI/QTrap/MS/MS).

Results

Aqueous extract of P. tomentosa showed a reasonable reduction in blood glucose level. Probably, the P. tomentosa effect on hyperglycemic and hyperlipidemic diabetic animals was associated with antioxidant properties, triglyceride levels, as well as liver enzymes. Meanwhile, LC-ESI/LTQOrbitrap/MS/MS analysis led to identification of double-linked cardenolides along with cardenolides and flavone glycosides as the main bioactive compounds.

Conclusion

The extract decreased the glucose level and induced a beneficial effect on the lipid profile, probably due to the presence of cardenolide glycosides.

Cytotoxicity, apoptosis inducing activity and Western blot analysis of tanshinone derivatives from Stachys parviflora on prostate and breast cancer cells

Cytotoxic activities of methanolic crude extract of Stachys parviflora (Lamiaceae family) and its sub-fractions were primarily evaluated against human breast adenocarcinoma (MCF-7 and MDA-MB-231) and prostate (PC3) cell lines. The methanolic extract exhibited the highest activity, and was chosen for the isolation procedure. Four diterpenoid quinones, namely miltirone [1], tanshinone IIA [2], 1-hydroxy-tanshinone IIA [3], and cryptotanshinone [4] were isolated. Notably, this is the first report on the isolation and/or characterization of the mentioned diterpenoids from the Stachys genus. In this study, 1-hydroxy-tanshinone IIA [3] displayed the highest cytotoxicity among the isolated compounds. The mechanism of the cytotoxicity of methanolic extract and isolated compounds was further investigated by the utilization of propidium iodide staining (PI) assay. The results showed that the methanolic extract and 1-hydroxy-tanshinone IIA [3] enhanced DNA fragmentation in PC3 and MCF-7 cells. Moreover, the western blotting analysis demonstrated increasing and decreasing protein levels of Bax and Bcl2, respectively, and cleaved poly ADP-ribose polymerase (PARP). Further bioassay-guided phytochemical assessments of S. parviflora can be suggested as a promising approach for discovering potent bioactive secondary metabolites.

Structural Diversity of Complex Phloroglucinol Derivatives from Eucalyptus Species

Several species of the genus Eucalyptus are used in many traditional medicine systems for the treatment of respiratory tract infections, colds, flu, sore throats, and bronchitis. The genus Eucalyptus (Myrtaceae) is a well-known natural source of bioactive phloroglucinols. These polyphenolic compounds bear an aromatic phenyl ring with three hydroxy groups (1,3,5-trihydroxybenzene) which have been exhibiting a variety of biological activities such as antimicrobial, anticancer, anti-allergic, anti-inflammatory, and antioxidant activities. This review summarizes the literature published from 1997 until the end of 2021 and addresses the structure diversity of phloroglucinols isolated from Eucalyptus species and their biological activities. Phloroglucinol-terpene adducts are the main class of compounds that have been reported in this genus.

A review of the protective effects of chlorogenic acid against different chemicals

Chlorogenic acid (CGA) is a naturally occurring non-flavonoid polyphenol found in green coffee beans, teas, certain fruits, and vegetables, that exerts antiviral, antitumor, antibacterial, and antioxidant effects. Several in vivo and in vitro studies have demonstrated that CGA can protect against toxicities induced by chemicals of different classes such as fungal/bacterial toxins, pharmaceuticals, metals, pesticides, etc., by preservation of cell survival via reducing overproduction of nitric oxide and reactive oxygen species and suppressed pro-apoptotic signaling. CGA antioxidant effects mediated through the Nrf2-heme oxygenase-1 signaling pathway were shown to enhance the levels of antioxidant enzymes such as superoxide dismutase, catalase, glutathione-S-transferases, glutathione peroxidase, and glutathione reductase as well as glutathione content. Also, CGA could suppress inflammation via inhibition of toll-like receptor 4 and MyD88, and the phosphorylation of inhibitor of kappa B and p65 subunit of NF-κB, resulting in diminished levels of downstream inflammatory factors including interleukin (IL)-1 β, IL-6, tumor necrosis factor-α, macrophage inflammatory protein 2, cyclooxygenase-2, and prostaglandin E2. Moreover, CGA inhibited apoptosis by reducing Bax, cytochrome C, and caspase 3 and 9 expression while increasing Bcl-2 levels. The present review discusses several mechanisms through which CGA may exert its protective role against such agents. Chemical and natural toxic agents affect human health. Phenolic antioxidant compounds can suppress free radical production and combat these toxins. Chlorogenic acid is a plant polyphenol present in the human diet and exerts strong antioxidant properties that can effectively help in the treatment of various toxicities.

Bioactive terpenoids derived from plant endophytic fungi: An updated review (2011-2020)

Plant endophytes have been considered as novel sources of naturally occurring compounds with various biological activities, including cytotoxic, antimicrobial, anti-inflammatory, anticancer, herbicides, antileishmanial and antioxidant. A variety of specialised products, comprising terpenoids, alkaloids, polyketides, phenolic compounds, coumarins, and quinone derivatives have been reported from various strains. An increasing number of products, especially terpenoids, are being isolated from endophytes. Herein, the isolated new terpenoids from plant endophytic fungi, their hosts, as well as biological activities, from January 2011 until the end of 2020 are reviewed. In this period, 516 terpenoids are classified into monoterpenes (5), sesquiterpenes (299), diterpenes (76), sesterterpens (22), meroterpenes (83), triterpenes (29), and other terpenoids (2), were isolated from different plant endophytic fungi species.

Cytotoxic sesquiterpene lactones and lignans from Cousinia turkmenorum Bornm (Asteraceae)

Seven sesquiterpene lactones, chlorophyssopifolin E (1), aguerin B (2), repdiolide triol (3), solistitiolide (4), aitchisonolide (5), sinicin B (6), cynaropicrin (7), along with four lignans arctigenin (8), arctiin (9), matairesinol (10), and matairesinoside (11) were isolated for the first time from the aerial parts of Cousinia turkmenorum Bornm. Among the isolated compounds, aguerin B (2) showed the most cytotoxic activity against MCF7 cell lines with IC₅₀ value of 18.9 μM. Findings of this study could be useful for the development of new anticancer agents from nature.

From plants to antimicrobials: Natural products against bacterial membranes

Bacterial membrane barrier provides a cytoplasmic environment for organelles of bacteria. The membrane is composed of lipid compounds containing phosphatide protein and a minimal amount of sugars, and is responsible for intercellular transfers of chemicals. Several antimicrobials have been found that affect bacterial cytoplasmic membranes. These compounds generally disrupt the organization of the membrane or perforate it. By destroying the membrane, the drugs can permeate and replace the effective macromolecules necessary for cell life. Furthermore, they can disrupt electrical gradients of the cells through impairment of the membrane integrity. In recent years, considering the spread of microbial resistance and the side effects of antibiotics, natural antimicrobial compounds have been studied by researchers extensively. These molecules are the best alternative for controlling bacterial infections and reducing drug resistance due to the lack of severe side effects, low cost of production, and biocompatibility. Better understanding of the natural compounds' mechanisms against bacteria provides improved strategies for antimicrobial therapies. In this review, natural products with antibacterial activities focusing on membrane damaging mechanisms were described. However, further high-quality research studies are needed to confirm the clinical efficacy of these natural products.

Quercetin and its role in modulating endoplasmic reticulum stress: A review

The endoplasmic reticulum (ER) is the place where proteins and lipids are biosynthesized and where transmembrane proteins are folded. Both pathological and physiological situations may disturb the function of the ER, resulting in ER stress. Under stress conditions, the cells initiate a defensive procedure known as the unfolded protein response (UPR). Cases of severe stress lead to autophagy and/or the induction of cell apoptosis. Many studies implicate ER stress as a major factor contributing to many diseases. Therefore, the modulation of ER stress pathways has become an attractive therapeutic target. Quercetin is a plant-derived metabolite belonging to the flavonoids class which presents a range of beneficial effects including anti-inflammatory, cardioprotective, anti-oxidant, anti-obesity, anti-carcinogenic, anti-atherosclerotic, anti-diabetic, anti-hypercholesterolemic, and anti-apoptotic activities. Quercetin also has anti-cancer activity, and can be used as an adjuvant to decrease resistance to cancer chemotherapy. Furthermore, the effect of quercetin can be increased with the help of nanotechnology. This review discusses the role of quercetin in the modulation of ER stress (and related diseases) and provides novel evidence for the beneficial use of quercetin in therapy.

Protective effects of curcumin against iron-induced toxicity

Iron is an essential element in cellular metabolism that participates in many biochemical reactions. Nevertheless, iron overload in the body is the cause of damage in some organs including liver, glands, brain, heart, gastrointestinal tract and lung. Iron chelation therapy could be considered as an effective approach for removing excess iron. Deferoxamine, deferiprone and deferasirox are three common iron chelators in clinical practice but cause several side effects. In this context, the use of curcumin, a dietary phytochemical derived from turmeric, as a natural and safe antioxidant with iron-chelating activity may be a useful strategy for the management of iron overload. This review focuses on the deleterious effect of iron accumulation in different organs of the body as well as the therapeutic potential of curcumin against iron-induced toxicity.

UPLC-PDA-ESI-QTOF-MS/MS and GC-MS analysis of Iranian Dracocephalum moldavica L

Dracocephalum moldavica L. is a significant component in the Iranian food basket. This study aimed to investigate the bioactive compounds and biological activities of different extracts obtained from D. moldavica aerial parts. From the aerial parts, a crude methanolic (MeOH) extract and its four sub-fractions, that is, petroleum ether (Pet), ethyl acetate (EtOAc), n-butanol (n-BuOH), and aqueous (water) extracts were obtained. The total phenolic and flavonoid contents as well as the antioxidant and cytotoxic activities of the extracts were determined. Moreover, the phytochemical profiles of the essential oil (EO) and of those extracts with the highest antioxidant activity measured by GC/MS and UPLC-PDA-ESI-QTOF-MS/MS. Results showed that the highest concentrations of phenols and flavonoids as well as the most potent antioxidant potential according to the DPPH method were determined in the EtOAc and MeOH extracts with IC50 values of 22.0 and 34.4 µg.ml-1, respectively. Quantitative analysis of these extracts was subsequently performed by UPLC-PDA-ESI-QTOF-MS/MS. Both extracts contained mainly rosmarinic acid, caffeic acid, and 2-hydroxycinnamic acid, which may be responsible for their high antioxidant activity. Moreover, none of the extracts showed cytotoxic effects against MCF7, SW48, and a normal cell line of mouse embryonic fibroblast cells (NIH/3T3) in the tested concentrations (up to 400 μg.ml-1). Additionally, GC-MS analysis showed that oxygenated monoterpenes (55.4%) were the main constituents of the EO of D. moldavica.

Anticancer Potential of Aguerin B, a Sesquiterpene Lactone Isolated from Centaurea behen in Metastatic Breast Cancer Cells

BACKGROUND

Breast carcinoma is a malignant disease that represents the most common non-skin malignancy and a chief reason of cancer death in women. Large interest is growing in the use of natural products for cancer treatment, especially with goal of suppression angiogenesis, tumor cell growth, motility, as well as invasion and metastasis with low/no toxicity. It is evident from recent patents on the anticancer properties of sesquiterpene lactones such as parthenolide.

OBJECTIVE

In this study, using MDA-MB-231 cells of a human breast adenocarcinoma, the effects of aguerin B, as a natural sesquiterpene lactone, has been evaluated, in terms of the expression of metastatic-related genes (Pak-1, Rac-1 and HIF-1α).

METHODS

Cytotoxicity of aguerin B was tested toward MDA-MB-231 breast tumor cells using MTT. Scratch assay was accomplished to evaluate the tumor cell invasion. To understand the underlying molecular basis, the mRNA expressions were evaluated by real time PCR.

RESULTS

It was found that aguerin B significantly inhibited human breast cancer cell growth in vitro (IC50 = 2μg/mL) and this effect was accompanied with a persuasive suppression on metastasis. Our results showed that aguerin B in IC50 concentration down-regulated Rac-1, Pak-1, Hif-1α and Zeb-1 transcriptional levels.

CONCLUSION

Taken together, this study demonstrated that aguerin B possessed potential anti-metastatic effect, suggesting that it may consider as a potential multi target bio compound for treatment of breast metastatic carcinoma.

Regulation of microRNA-21 expression by natural products in cancer

Natural products have been of much interest in research studies owing to their wide pharmacological applications, chemical diversity, low side effects, and multitarget activities. Examples of these compounds include matrine, sulforaphane, silibinin, curcumin, berberin, resveratrol, and quercetin. Some of the present anticancer drugs, such as taxol, vincristine, vinblastine, and doxorubicin are also derived from natural products. The anti-carcinogenic effects of these products are partly mediated through modulation of microRNA-21 (miR-21) expression. To date, numerous downstream targets of miR-21 have been recognized, which include phosphatase and tensin homolog (PTEN), ras homolog gene family member B (RHOB), phosphoinositide 3-kinase/protein kinase B (PI3K/Akt), programmed cell death 4 (PDCD4), signal transducer and activator of transcription (STAT)-3, and nuclear factor kappa B (NF-κB) pathways. These signaling pathways, their regulation by oncomiR-21 in cancer, and the modulating impact of natural products are the main focus of this review.

A Review of the Phytochemistry and Antimicrobial Properties of Origanum vulgare L. and Subspecies

Origanum vulgare L. (O. vulgare) is an important medicinal herb of the family Lamiaceae. In the current study, we explained the critical evaluation of traditional uses, the phytochemistry and the antimicrobial properties of O. vulgare and its subspecies, with a focus on the mechanisms of actions of the most important phytochemicals from O. vulgare subspecies. The most important phytochemicals of O. vulgare are volatile (essential oil) and non-volatile phenolic compounds (phenolic acids & flavonoids). The constituents of the O. vulgare essential oil (EO) include high percentages of thymol and carvacrol with excellent antimicrobial activity alone or in combination with other antibiotics. Interesting results have been reported the remarkable antimicrobial activities of infusion or tea products of O. vulgare with a high amount of EO against multidrug-resistant bacterial and fungal microorganism (such as Escherichia coli, Staphylococcus aureus, Candida albicans and Pseudomonas aeruginosa). The most important antibacterial mechanisms of O. vulgare are enzyme inhibition, efflux pump inhibition, ATP depletion, biofilm formation inhibition and cytoplasmic membrane damage. The antimicrobial activity of the hirtum subspecies has been confirmed in different in-vitro and in-vivo studies. The present review confirms the clinical and preclinical research showing the O. vulgare and its subspecies antimicrobial effects.

Cardioprotective Effects of Natural Products via the Nrf2 Signaling Pathway

Due to its poor regenerative capacity, the heart is specifically vulnerable to xenobiotic- induced cardiotoxicity, myocardial ischaemia/reperfusion injury and other pathologies. Nuclear factor erythroid-2-related factor 2 (Nrf2) is considered as an essential factor in protecting cardiomyocytes against oxidative stress resulting from free radicals and reactive oxygen species. It also serves as a key regulator of antioxidant enzyme expression via the antioxidant response element, a cis-regulatory element, which is found in the promoter region of several genes encoding detoxification enzymes and cytoprotective proteins. It has been reported that a variety of natural products are capable of activating Nrf2 expression, and in this way, increase the antioxidant potential of cardiomyocytes. In the present review, we consider the cardioprotective activities of natural products and their possible therapeutic potential.

4,5-Seco-5,10-friedo-abietane-type diterpenoids with anticancer activity from Salvia atropatana Bunge

The purpose of this study is cytotoxicity-guided isolation of the petroleum ether fraction from the roots of Salvia atropatana for the first time, which has shown to growth inhibition and apoptosis induction in MCF-7 and PC3 cells. Bioassay-guided isolation method was conducted for finding compounds with highest cytotoxicity. Different extracts were prepared from the roots of Salvia atropatana. All extracts were tested for their cytotoxic activity against three cancer cell lines (PC3, MCF-7, and MDA-MB-231). The most cytotoxic extract was chosen for further isolation by column chromatography and HPLC. The chemical structures were determined by spectroscopic methods including 1D and 2D NMR. From the petroleum ether extract, four abietane-type diterpenoids, including a new abietane-type diterpenoid, named atropatanene (1), together with three known diterpenoids, 7α-acetoxyroyleanone (2), and a mixture of two isomers, saprorthoquinone and aethiopinone (3+4), were isolated. The latter exhibited substantial cytotoxicity with IC₅₀ value of 8.73 μg/ml against PC3 cells and led to an increasing number of cells in the subG1 region and an increase in the amount of Bax and cleavage of PARP protein, indicating apoptotic cell death. Owing to its numerous biological activities, Salvia species could be represented as a natural potential source against several cancer cell lines.

Naphthoquinone Derivatives Isolated from Plants: Recent Advances in Biological Activity

Naturally occurring naphthoquinones (NQs) comprising highly reactive small molecules are the subject of increasing attention due to their promising biological activities such as antioxidant, antimicrobial, apoptosis-inducing activities, and especially anticancer activity. Lapachol, lapachone, and napabucasin belong to the NQs and are in phase II clinical trials for the treatment of many cancers. This review aims to provide a comprehensive and updated overview on the biological activities of several new NQs isolated from different species of plants reported from January 2013 to January 2020, their potential therapeutic applications and their clinical significance.

Ellagic Acid: A Logical Lead for Drug Development?

BACKGROUND

Naturally occurring polyphenols are the subject of increasing attention due to their potent antioxidant activity and their marked effects on the prevention of various oxidative stress-associated diseases such as cancer. Ellagic acid (EA) is an herbal polyphenol that is structurally a condensed dimer of gallic acid.

METHODS

This review aims to provide a comprehensive and updated overview on the biological activities of EA and potential therapeutic applications.

RESULTS

EA is found in fruits and nuts, either in the combined form with hexahydroxydiphenic acid or in the bound form (ellagitannins). EA exhibits many biological properties such as antioxidant, anti-diabetic, anticancer and apoptosis-inducing activities. These biological and pharmacological properties are relevant to the treatment of several human diseases.

CONCLUSION

Owing to its multiple mechanisms of action, EA represents a potential therapeutic agent against human diseases particularly cancer.

Biological properties of metal complexes of curcumin

Curcumin, a naturally occurring phenolic compound isolated from Curcuma longa, has different pharmacological effects, including antiinflammatory, antimicrobial, antioxidant, and anticancer properties. However, curcumin has been found to have a limited bioavailability because of its hydrophobic nature, low-intestinal absorption, and rapid metabolism. Therefore, there is a need for enhancing the bioavailability and its solubility in water in order to increase the pharmacological effects of this bioactive compound. One strategy is curcumin complexation with transition metals to circumvent the abovementioned problems. Curcumin can undergo chelation with various metal ions to form metallo-complexes of curcumin, which may show greater effects as compared with curcumin alone. Promising results with metal curcumin complexes have been observed with regard to antioxidant, anticancer, and antimicrobial activity, as well as in treatment of Alzheimer's disease. The present review provides a concise summary of the characterization and biological properties of curcumin-metal complexes. © 2019 BioFactors, 45(3):304-317, 2019.

LC-ESI/LTQOrbitrap/MS/MS and GC-MS profiling of Stachys parviflora L. and evaluation of its biological activities

The use of some Stachys genus as herbal remedies is known and the aerial parts have a pharmaceutical interest, being used in Anatolia and Iran as wild tea. In this study, chemical composition, antimicrobial, antioxidant, and antiproliferative activities of the methanolic extract and essential oil (EO) of Stachys parviflora L. (S. parviflora) were evaluated. Qualitative analysis of metabolites of S. parviflora methanolic extract was studied using liquid chromatography coupled to high resolution mass spectrometry (LC-ESI/LTQOrbitrap/MS), evidencing the presence of phenolic acids and flavonoids derivatives. The EO was analyzed using gas chromatography coupled to mass spectrometry (GC/MS). Eighty-seven compounds were characterized in the EO of S. parviflora, of which α-terpenyl acetate (23.6%), β-caryophyllene (16.8%), bicyclogermacrene (9.3%), spathulenol (4.9%) and α-pinene (4.2%) were found to be the major components. The highest antimicrobial effect of EO was found to S. aureus and B. cereus (MIC = 0.01 μg/ml), while the highest activity of extract was against B. cereus (MIC = 125 μg/ml). The methanolic extract exhibited strong antioxidant activity in DPPH (IC₅₀ = 76.87 μg/ml) and β-carotene/linoleic acid assay (BCB, IC₅₀ = 188.47 μg/ml) methods. Furthermore, in vitro cytotoxicity evaluation against three cell lines namely human ovarian carcinoma (A2780), human colon carcinoma (HCT), and mouse melanoma cell line (B16F10), showed an anti-proliferative activity of the EO ranging from IC₅₀ value 30.95 μg/ml to 16.55 μg/ml. The results from this study have demonstrated the promising cytotoxic, antibacterial, and antifungal properties of S. parviflora, which could have wide potential applications in food and pharmaceutical industries.

Designing a tunable acoustic resonator based on defect modes, stimulated by selectively biased PZT rods in a 2D phononic crystal

Reconfigurable phononic crystals (PnCs) and related devices are highly attractive because of their flexibility for different applications. We present the design procedure for a tunable acoustic resonator based on a 2D PnC, consisting of a periodic array of piezoelectric rods of radii 175 μm as inclusions arranged in air background. A single point defect devised by a rod of radius 161 μm, replacing one of the inclusions, plays the role of the acoustic resonator, leading to a defect frequency in the phononic band gap (f_d ≈ 432 kHz). Applying a ∼1% strain to the defect rod, via an external voltage, tunes the defect resonant frequency within the phononic band gap. It is shown that the maximum tunability and the frequency shift depends on the defect size, and is achieved about Δf_d = 440 Hz for the defect with the expense of descending quality factor. Considering the pattern of the localized pressure field, we introduce a multi-defect structure with five symmetric defect rods, corresponding to the maxima of field distribution. It is shown that maximum frequency shift of the dominant defect frequency is achieved about Δf_d = 1.14 kHz for defect radius of 161 μm, when all five defect rods are strained. The proposed tunable filter based on multi-defect structure results in an enhancement of about 2.6 times in the maximum frequency shift, in comparison with the single defect structure, and introduces a promising approach for realizing tunable acoustic devices.

Curcumin: A naturally occurring autophagy modulator

Autophagy is a self-degradative process that plays a pivotal role in several medical conditions associated with infection, cancer, neurodegeneration, aging, and metabolic disorders. Its interplay with cancer development and treatment resistance is complicated and paramount for drug design since an autophagic response can lead to tumor suppression by enhancing cellular integrity and tumorigenesis by improving tumor cell survival. In addition, autophagy denotes the cellular ability of adapting to stress though it may end up in apoptosis activation when cells are exposed to a very powerful stress. Induction of autophagy is a therapeutic option in cancer and many anticancer drugs have been developed to this aim. Curcumin as a hydrophobic polyphenol compound extracted from the known spice turmeric has different pharmacological effects in both in vitro and in vivo models. Many reports exist reporting that curcumin is capable of triggering autophagy in several cancer cells. In this review, we will focus on how curcumin can target autophagy in different cellular settings that may extend our understanding of new pharmacological agents to overcome relevant diseases.

Selective and metal-free epoxidation of terminal alkenes by heterogeneous polydioxirane in mild conditions

Polydioxirane (PDOX) was prepared by the treatment of polysalicylaldehyde with Oxone and was found as a selective, highly efficient and heterogeneous reagent for epoxidation of alkenes which can be successfully isolated. This work also introduced a simpler, safer and milder way for epoxidation of alkenes with dioxirane groups than before. PDOX can be simply recovered from the reaction mixture by plain filtration and reused for eight runs without significant reactivity loss.

Screening of several biological activities induced by different sesquiterpene lactones isolated from Centaurea behen L. and Rhaponticum repens (L.) Hidalgo

This study aims to evaluate the in vitro cytotoxic, in vitro and in ovo anti-angiogenic effects and antimicrobial activity of sesquiterpene lactones (SLs) from two plants Centaurea behen and Rhaponticum repens (L.). Five SLs, including cynaropicrin (1), 4β,15-dehydro-3-dehydrosolstitialin A (2), aguerin B (3), janerin (4), cebellin E (5), and a flavone hispidulin (6) were isolated from C. behen (compounds 1-3) and R. repens (compounds 4-6). Cynaropicrin (1) and aguerin B (3) were characterised by strong cytotoxic activities against A2780 cells with IC₅₀ values of 1.15 and 1.62 μg mL^-1, respectively, comparable to that of doxorubicin (IC₅₀ = 1.17 μg mL^-1). The anti-angiogenic study showed the remarkable inhibitory effect of cynaropicrin (1) and aguerin B (3) on the proliferation and migration of HUVECs. In addition, cynaropycrin and aguerin B exhibited significant angio-inhibitory effects in CAM assay. These findings may be useful for the development of novel chemotherapeutic agents for the treatment of cancer.

Identification and biological activity of the volatile compounds of Glycyrrhiza triphylla Fisch. & C.A.Mey

Chemical composition and biological (antimicrobial, antioxidant and cytotoxic) activities of essential oils (EO) obtained from the aerial parts of Glycyrrhiza triphylla Fisch. & C.A.Mey (G. triphylla) were evaluated in the present study. The EO was isolated and analyzed using gas chromatography-mass spectrometry (GC-MS). Fifty-five compounds representing 99.3% of the total oil composition were identified. Major components of the oil were β-caryophyllene (25.4%), limonene (16.7%), β-myrcene (16.0%) and α-humulene (4.4%). The oil composition was dominated by the presence of sesquiterpene hydrocarbons comprising 43.6% of the total oil. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of the oil were determined against eight bacterial strains and one fungus. The EO showed a good antibacterial activity against both Gram-positive and Gram-negative bacteria. The most susceptible strain was Micrococcus luteus (MIC = 2.7 μg/mL, MBC = 43.6 μg/mL). The antioxidant potential of the EO was examined using DPPH and β-carotene/linoleic acid (BCB) assays. The oil was considerably active in the DPPH assay (IC₅₀ = 100.40 ± 0.03 μg/mL). Moreover, in vitro cytotoxic activity was assessed against six cancer cell lines using MTT assay. The EO showed no significant cytotoxic activity. In light of the present findings, G. triphylla oil may deserves to be further investigated for its potential therapeutic effects and also as a natural preservative in food industry.

The Absolute Configuration and Cytotoxic Properties of Roehybridine β-N-oxide

Roehybridine β- N-oxide (RNO) is a proaporphine-tryptamine dimer alkaloid from Roemeria hybrida. RNO possesses five stereogenic centers and so far its absolute configuration has not been determined. In this study, the absolute configuration of RNO was established as 6a S,7a R,6 R,9 S,10 R by comparing experimental and TDDFT calculated electronic circular dichroism (ECD) spectra. In addition, we have reported an amendment indicating exact 1H and 13C chemical shifts of RNO. RNO exhibited cytotoxic activity when tested in vitro against prostate cancer cell lines including PC3 and DU145. The IC50 values of RNO against PC3 and DU145 were 13.3 and 15.1 μg/mL, respectively.

The Absolute Configuration and Cytotoxic Properties of Roehybridine β-N-oxide

Roehybridine β-N-oxide (RNO) is a proaporphine-tryptamine dimer alkaloid froti Roemeria hybrida. RNO possesses five stefeogenic centers and so far. its absolute configuration has not been determined. In this study, the absolute configuration of RNO was established as 6aS,7aR,6R,9S,1OR by comparing experimental and TDDFT calculated electronic circular dichroism (ECD) spectra. In addition, we have reported an amendment indicating exact (1)H and (13)C chemical shifts of RNO. RNO exhibited cytotoxic activity when tested in vitro against prostate cancer cell lines including PC3 and DU145. The IC(50) values of RNO against PC3 and DU145 were 13.3 and 15.1 μg/mL, respectively.

Melissa officinalis L. - A review of its traditional uses, phytochemistry and pharmacology

ETHNOPHARMACOLOGICAL RELEVANCE

Melissa officinalis L. is a medicinal plant that has long been used in different ethno-medical systems especially in the European Traditional Medicine and the Iranian Traditional Medicine for the treatment of several diseases. It is also widely used as a vegetable and to add flavor to dishes

AIM OF THE REVIEW

This review aimed to provide a summary on the botanical characterization, traditional uses, phytochemistry, pharmacological activities, pharmacokinetics and toxicity of M. officinalis, and discusses research gaps and future opportunities for investigations on this plant.

MATERIALS AND METHODS

We extensively reviewed major unpublished old texts, and published and electronic literature on traditional medicines of different regions of the world to find traditional uses of M. officinalis. Electronic databases including Web of Science, PubMed, ScienceDirect, Google Scholar and Scopus were searched to find articles (published between 1956 and 2015) on pharmacology and phytochemistry of M. officinalis.

RESULTS

Traditional uses of M. officinalis have been recorded mostly in European countries, Mediterranean region and Middle East countries. Phytochemical investigations revealed that this plant contains volatile compounds, triterpenoids, phenolic acids and flavonoids. Crude extracts and pure compounds isolated from M. officinalis exhibited numerous pharmacological effects, from which only anxiolytic, antiviral and antispasmodic activities of this plant as well as its effects on mood, cognition and memory have been shown in clinical trials. AChE inhibitory activity, stimulation of the acetylcholine and GABAA receptors, as well as inhibition of matrix metallo proteinase-2 are the main mechanisms proposed for the widely discussed neurological effects of this plant.

CONCLUSIONS

Modern pharmacological studies have now validated many traditional uses of M. officinalis. The data reviewed here revealed that M. officinalis is a potential source for the treatment of a wide range of diseases especially anxiety and some other CNS disorders, though confirmatory trials are warranted to substantiate these effects in the clinical setting. Data regarding many aspects of this plant such as mechanisms of actions, pharmacokinetics, adverse effects of the extracts, potential interactions with standard-of-care medications and active compounds is still limited which call for additional studies particularly in humans.