Cyclooxygenase‐2 inhibitory and antioxidant compounds from the truffle Elaphomyces granulatus

The ethanol extract of fruiting bodies of Elaphomyces granulatus, a truffle‐like fungus, was evaluated for cyclooxygenase‐2 (COX‐2) enzyme inhibitory and antioxidant activities. Inhibition of COX‐2 activity was evaluated in mouse macrophages (RAW 264.7). The extract of E. granulatus caused a 68% inhibition of COX‐2 activity at 50 µg/mL. Bioassay‐guided investigation led to the isolation and identification of two active compounds, syringaldehyde and syringic acid. Syringaldehyde moderately inhibited COX‐2 activity with an IC₅₀ of 3.5 µg/mL, while syringic acid strongly inhibited COX‐2 activity with an IC₅₀ of 0.4 µg/mL. The antioxidant activity of the extract and isolated compounds was evaluated in HL‐60 cells by the DCFH‐DA method. The extract of E. granulatus showed a potent antioxidant effect, with an IC₅₀ of 41 µg/mL. Of the pure compounds, syringic acid displayed a strong antioxidant activity, with an IC₅₀ of 0.7 µg/mL, while syringaldehyde showed no activity in the assay. Copyright © 2008 John Wiley & Sons, Ltd.     

Antiplasmodial and cytotoxic activity of phloroglucinol derivatives from Hypericum erectum thunb

The chloroform extracts of whole plants of Hypericum erectum were investigated for antiplasmodial activity against chloroquine‐sensitive strains of Plasmodium falciparum. Five phloroglucinol derivatives, otogirin (1), otogirone (2), erectquione A (3), erectquione B (4), and erectquione C (5) were isolated from the whole plants of H. erectum. Also, five compounds were evaluated for in vitro antiplasmodial activities as well as their cytotoxic potential on SK‐OV‐3 cancer cell line cells. Compounds 2, 4 showed notable growth inhibitory activity against chloroquine‐sensitive strains of Plasmodium falciparum with IC₅₀ values from 5.6 and 7.2 μM. This compound showed no significant cytotoxicity (IC₅₀ > 150 μM) evaluated using SK‐OV‐3 cancer cell line cells. Copyright © 2010 John Wiley & Sons, Ltd.     

Nettle extract (Urtica dioica) affects key receptors and enzymes associated with allergic rhinitis

A nettle (Urtica dioica) extract shows in vitro inhibition of several key inflammatory events that cause the symptoms of seasonal allergies. These include the antagonist and negative agonist activity against the Histamine‐1 (H₁) receptor and the inhibition of mast cell tryptase preventing degranulation and release of a host of pro‐inflammatory mediators that cause the symptoms of hay fevers. The nettle extract also inhibits prostaglandin formation through inhibition of Cyclooxygenase‐1 (COX‐1), Cyclooxygenase‐2 (COX‐2), and Hematopoietic Prostaglandin D₂ synthase (HPGDS), central enzymes in pro‐inflammatory pathways. The IC₅₀ value for histamine receptor antagonist activity was 251 (±13) µg mL^?1 and for the histamine receptor negative agonist activity was 193 (±71) µg mL^?1. The IC₅₀ values for inhibition of mast cell tryptase was 172 (±28) µg mL^?1, for COX‐1 was 160 (±47) µg mL^?1, for COX‐2 was 275 (±9) µg mL^?1, and for HPGDS was 295 (±51) µg mL^?1. Through the use of DART TOF‐MS, which yields exact masses and relative abundances of compounds present in complex mixtures, bioactives have been identified in nettle that contribute to the inhibition of pro‐inflammatory pathways related to allergic rhinitis. These results provide for the first time, a mechanistic understanding of the role of nettle extracts in reducing allergic and other inflammatory responses in vitro. Copyright © 2009 John Wiley & Sons, Ltd.     

Antibacterial and Antimycobacterial Lignans and Flavonoids from Larrea tridentata

Three lignans and four flavonoids were isolated and characterized from Larrea tridentata and compounds were tested against 16 bacterial species/strains. Results showed that: dihydroguaiaretic acid (1) had activity towards methicillin resistant (MR) Staphylococcus aureus (minimum inhibitory concentration (MIC) 50 µg/mL) and multidrug‐resistant (MDR) strains of Mycobacterium tuberculosis (MIC 12.5–50 µg/mL); 4‐epi‐larreatricin (2) was active against Enterobacter cloacae (MIC 12.5 µg/mL), as well as sensitive (MIC 50 µg/mL) and MDR strains of M. tuberculosis (MIC 25 µg/mL). 3′‐Demethoxy‐6‐O‐demethylisoguaiacin (3) displayed activity against sensitive and resistant S. aureus (MIC 25 µg/mL), Enterococcus faecalis (MIC 12.5 µg/mL), Escherichia coli (MIC 50 µg/mL), E. cloacae (MIC 12.5 µg/mL) and MDR strains of M. tuberculosis (MIC 12.5 µg/mL). 5,4′‐Dihydroxy‐3,7,8,3′‐tetramethoxyflavone (4) and 5,4′‐dihydroxy‐3,7,8‐trimethoxyflavone (5) were active against M. tuberculosis MDR strains having MIC values of 25 and 25–50 µg/mL, respectively, while 5,4′‐dihydroxy‐7‐methoxyflavone (6) was active against S. aureus (MIC 50 µg/mL) and E. faecalis (MIC 50 µg/mL). We concluded that lignan 3 is the main compound responsible for the antibacterial activity of L. tridentata. Lignans 1 and 2 as well as flavonoid 6 contribute with some degree of antibacterial activity. On the other hand, compounds 1, 2, 3, 4 and 5 contributed to the antimycobacterial activity found in L. tridentata. Copyright © 2012 John Wiley & Sons, Ltd.     

Zingiber officinale (ginger) compounds have tetracycline‐resistance modifying effects against clinical extensively drug‐resistant Acinetobacter baumannii

Extensively drug‐resistant Acinetobacter baumannii (XDRAB) is a growing and serious nosocomial infection worldwide, such that developing new agents against it is critical. The antimicrobial activities of the rhizomes from Zingiber officinale, known as ginger, have not been proven in clinical bacterial isolates with extensive drug‐resistance. This study aimed to investigate the effects of four known components of ginger, [6]‐dehydrogingerdione, [10]‐gingerol, [6]‐shogaol and [6]‐gingerol, against clinical XDRAB. All these compounds showed antibacterial effects against XDRAB. Combined with tetracycline, they showed good resistance modifying effects to modulate tetracycline resistance. Using the 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) radical scavenging method, these four ginger compounds demonstrated antioxidant properties, which were inhibited by MnO₂, an oxidant without antibacterial effects. After the antioxidant property was blocked, their antimicrobial effects were abolished significantly. These results indicate that ginger compounds have antioxidant effects that partially contribute to their antimicrobial activity and are candidates for use in the treatment of infections with XDRAB. Copyright © 2010 John Wiley & Sons, Ltd.     

The phytochemical and anti‐inflammatory studies of Dillenia suffruticosa leaves

The Dillenia suffruticosa leaves (Dilleniaceae), a folk medicine recommended in Southeast Asia for treating inflammation, were phytochemically studied for the first time and assessed for suppression of λ‐carrageenan‐induced paw oedema in rats. The crude methanolic extract orally administered at 5,000 mg/kg, displayed no toxicity and at 250 to 1,000 mg/kg significantly suppressed the paw oedema. Two‐isolated triterpenoids, betulinic acid (1) and koetjapic acid (2) orally administered at 50 mg/kg, significantly reduced the paw oedema, (p < 0.001) and (p < 0.005) at the fourth h onwards to 47.36% ± 2.23 and 53.43% ± 7.09, respectively, from 95.90% ± 6.88 oedema induced by λ‐carrageenan alone. 1 and the isolated flavonoids of vitexin (3), tiliroside (4), and kaempferol (5), displayed moderately more of cyclooxygenase (COX)‐2 than COX‐1 enzyme inhibition, whereas 2 was slightly more inhibition of COX‐1. The in silico molecular docking studies provided support to the in vitro COX studies that the isolated compounds formed H‐bonding with the amino acid residues at the COX‐2 catalytic sites. The triterpenoids were bound to the peroxidase, possibly inhibiting the peroxidase reaction, whereas the flavonoids interacted more at the cyclooxygenase, resembling celecoxib, therefore providing evidences that these compounds were responsible for the anti‐inflammatory properties of D. suffruticosa.     

Antioxidative effects of curcumin and its analogues against the free‐radical‐induced peroxidation of linoleic acid in micelles

Curcumin (1,7‐bis(4‐hydroxy‐3‐methoxyphenyl)‐1,6‐heptadiene‐3,5‐dione, 1) is a yellow ingredient isolated from turmeric (curcumin longa). Many health benefits have been claimed for curcumin, and these have generally been ascribed to its radical‐trapping antioxidant properties. In order to find more active antioxidants with 1 as the lead compound, we synthesized curcumin analogues, i.e., 1,7‐bis(3,4‐dihydroxyphenyl)‐1,6‐heptadiene‐3,5‐dione (2), 1‐(3,4‐dihydroxyphenyl)‐7‐(4‐hydroxy‐3‐methoxyphenyl)‐1,6‐heptadiene‐3,5‐dione (3), 1‐(4‐hydroxy‐3‐methoxyphenyl)‐7‐(4‐hydroxyphenyl)‐1,6‐heptadiene‐3,5‐dione (4), 1,7‐bis (4‐hydroxyphenyl)‐1,6‐heptadiene‐3,5‐dione (5), 1,7‐bis(3,4‐dimethoxyphenyl)‐1,6‐heptadiene‐3,5‐dione (6), 1,7‐bis(4‐methoxyphenyl)‐1,6‐heptadiene‐3,5‐dione (7), and 1,7‐diphenyl‐1,6‐heptadiene‐3,5‐dione (8). Antioxidative effects of curcumin and these analogues against the peroxidation of linoleic acid were studied in sodium dodecyl sulfate (SDS) and cetyltrimethylammonium bromide (CTAB) micelles. The peroxidation was initiated thermally by a water‐soluble initiator 2,2′‐azobis(2‐amidinopropane hydrochloride) (AAPH), and reaction kinetics were monitored by the formation of linoleic acid hydroperoxides. Kinetic analysis of the antioxidation process demonstrates that these compounds, except 6, 7 and 8, are effective antioxidants in micelles by H‐atom abstraction from the phenolic groups. Compounds 2 and 3, which bear ortho‐diphenoxyl functionality, possess significantly higher antioxidant activity than curcumin and other analogues, and the 4‐hydroxy‐3‐methoxyphenyl group also plays an important role in the antioxidative activity. In addition, the synergistic antioxidant effect of these compounds with α‐tocopherol (vitamin E) in micelles was also studied by following the formation of linoleic acid hydroperoxides and the consumption of α‐tocopherol. It was found that these compounds could not synergistically interact with α‐tocopherol in micelles. Copyright © 2009 John Wiley & Sons, Ltd.     

Hepatoprotective activity of praecoxin A isolated from Melaleuca ericifolia against carbon tetrachloride‐induced hepatotoxicity in mice. Impact on oxidative stress,inflammation, and apoptosis

The hepatoprotective activity of praecoxin A, an ellagitannin from Melaleuca ericifolia, was determined against CCl₄‐induced toxicity in mice. Praecoxin A was administered (25, 50, and 100 mg/kg) for 5 days followed by CCl₄. Praecoxin A markedly ameliorated the CCl₄‐induced increase in AST (by 19, 52, and 56%), ALP (22, 45, and 48%), ALT (11, 47, and 54%), total bilirubin (14, 27, and 28%), and MDA (26, 44, and 51%) at the tested doses, respectively, as compared with CCl₄ group. It was evident that praecoxin A significantly (p < 0.001) increased the antioxidant parameters GSH (45, 99, and 137%) and SOD (61, 129, and 159%). Histological findings revealed a marked amelioration of hepatocyte degeneration, necrosis, inflammatory cell infiltration, and hemorrhage in the groups treated with praecoxin A. COX‐2 and caspase‐3 hepatic expressions were significantly downregulated (p < 0.001) in praecoxin A‐treated groups (up to 57, 83, and 93% for COX‐2 and by 30, 82, and 99% for caspase‐3). These findings suggest that praecoxin A exerts a beneficial effect against oxidative stress by reducing lipid peroxidation, enhancing the antioxidant defense status, and protecting against the histopathological changes induced by CCl₄. This study highlights a promising natural hepatoprotective candidate derived from M. ericifolia that might be an alternative to silymarin.     

Antibacterial activity and synergistic antibiotic mechanism of trialdehyde phloroglucinol against methicillin-resistant Staphylococcus aureus

The emergence of methicillin-resistant Staphylococcus aureus (MRSA) has become a critical global concern. Identifying new anti-S. aureus agents or therapeutic strategies are urgently needed to treat S. aureus infection. The present study investigated the antibacterial activity of 16 phenolic compounds against MRSA, four of which exhibited antibacterial activity. Their antibacterial activities increased in a dose-dependent manner but showed different responses with the extension of treatment time. Trialdehyde phloroglucinol (TPG) and 2-nitrophloroglucinol (NPG) maintained stable antibacterial activity; however, that of dichlorophenol and myricetin decreased rapidly over 24 hr of treatment. Checkerboard and time-kill assays indicated that TPG and NPG exhibited strong synergistic antibacterial activities with penicillin or bacitracin. Microscopic observation and membrane integrity analysis showed that the combination of TPG and penicillin destroyed the MRSA cell membrane, resulting in the leakage of intracellular biomacromolecules, marked changes in surface zeta potential, and the collapse of membrane potential. Moreover, the combination significantly decreased penicillinase activity and penicillin-binding protein 2a mRNA expression, inhibiting MRSA growth. Taken together, these results demonstrated that the combination of the phloroglucinol derivative TPG and penicillin has significant synergistic anti-MRSA activity and can serve as a potential therapeutic strategy to treat MRSA infections.     

In vitro Antimicrobial Activity of Royleanone Derivatives Against Gram‐Positive Bacterial Pathogens

Infections caused by multiresistant bacterial pathogens are a significant problem worldwide, turning the search for natural compounds to act as alternatives to antibiotics of major importance. The aim of the present study was to investigate the in vitro antimicrobial activity of 7α‐acetoxy‐6β‐hydroxyroyleanone (1), isolated from Plectranthus grandidentatus (Lamiaceae), and 11 additional royleanone abietane derivatives of 1 (2–12) against important Gram‐positive human bacterial pathogens. Results showed that the aromatic and alkylic esters 2, 3 and 5 are more active than 1 against Enterococcus and Staphylococcus (minimum inhibitory concentration (MIC) values ranging from 0.98 to 62.50 µg/mL). Moreover, 7α‐acetoxy‐6β‐hydroxy‐12‐O‐(4‐chloro)benzoylroyleanone (2) gave rise to a new antibacterial‐prototype (MIC values of 3.91–15.63 µg/mL against Staphylococcus and of 0.98–3.91 µg/mL against Enterococcus). The results showed that the compounds under analysis also present antimicrobial activity against resistant bacteria. The hydrophobic extra‐interactions with bacterial targets seem to play an important role on the activity of royleanones derivatives. Copyright © 2013 John Wiley & Sons, Ltd.     

Becatamide Found in Houttuynia cordata Suppresses P‐selectin Expression Via Inhibiting COX Enzyme,Not Increasing cAMP in Platelets

Atherosclerosis is a well‐known inflammatory cardiovascular disease. Recent studies suggested potential anti‐atherosclerosis effects of becatamide found in Houttuynia cordata. Therefore, in this study, we investigated potential effect of becatamide (1) and its analogues (enferamide (2), veskamide (3), oretamide (4) and amkamide (5)) on cyclooxygenase (COX)‐1 and ‐2 and the production of cyclic adenosine monophosphate (cAMP), which are critically involved in platelet activation. Among them, becatamide was the most potent compound able to inhibit COX‐1 (IC₅₀ = 0.27 µm ) and ‐2 (IC₅₀ = 0.78 µm ) (p < 0.05). The decreasing order of COX‐1 and ‐2 inhibition activity was becatamide > veskamide > enferamide > oretamide > amkamide. As a result of the inhibition, the production of thromboxane B2 and P‐selectin expression were suppressed by 35% (p < 0.05) and 28% (p < 0.05), respectively, in mouse blood treated with becatamide (0.25 µm ). However, becatamide did not increase intracellular cAMP in platelets. Therefore, the suppression of P‐selectin expression was not blocked by beta 2‐adrenoceptor antagonists, suggesting that the COX inhibition is likely an underlying mechanism for the P‐selectin suppression. In summary, becatamide may be a potent compound to inhibit platelet activation by inhibiting COX enzymes, not by increasing cAMP. Published 2015. This article is a U.S. Government work and is in the public domain in the USA.     

Withanolide sulfoxide from Aswagandha roots inhibits nuclear transcription factor‐kappa‐B,cyclooxygenase and tumor cell proliferation

Investigation of the methanol extract of Aswagandha (Withania somnifera) roots for bioactive constituents yielded a novel withanolide sulfoxide compound (1) along with a known withanolide dimer ashwagandhanolide (2) with an S‐linkage. The structure of compound 1 was established by extensive NMR and MS experiments. Compound 1 was highly selective in inhibiting cyclooxygenase‐2 (COX‐2) enzyme by 60% at 100 µm with no activity against COX‐1 enzyme. The IC₅₀ values of compound 1 against human gastric (AGS), breast (MCF‐7), central nervous system (SF‐268) and colon (HCT‐116) cancer cell lines were in the range 0.74–3.63 µm. Both S‐containing dimeric withanolides, 1 and 2, completely suppressed TNF‐induced NF‐κB activation when tested at 100 µm. The isolation of a withanolide sulfoxide from W. somnifera roots and its ability to inhibit COX‐2 enzyme and to suppress human tumor cell proliferation are reported here for the first time. In addition, this is the first report on the abrogation of TNF‐induced NF‐κB activation for compounds 1 and 2. Copyright © 2009 John Wiley & Sons, Ltd.     

Acetylcholinesterase Inhibition,Antioxidant, Antiinflammatory,Antimicrobial and Phytochemical Properties of Huernia hystrix

Huernia species are typical famine‐food plants consumed in southern Ethiopia. H. hystrix is a heavily exploited ethnomedicinal succulent plant traded in traditional medicine systems especially on South Africa's eastern seaboard. This study investigated the acetylcholinesterase (AChE) inhibition, antioxidant, antiinflammatory and antimicrobial properties of extracts obtained from the stems and roots of this plant. At the same concentration level (625.0, 312.5 or 156.3 µg/mL), the whole plant extract showed higher AChE inhibitory activity when compared with the stem and root extracts; a finding suggesting the presence of AChE inhibitors acting additively or synergistically in the whole plant extract. The roots showed strong antioxidant activity (in DPPH and β‐carotene assays) comparable to that of butylated hydroxytoluene (BHT), indicating the presence of potent antioxidant compound(s) that can be exploited as alternatives for use in the food and cosmetic industries and/or as nutraceuticals. All the petroleum ether (PE) (except root PE) and dichloromethane (DCM) extracts demonstrated good inhibitory activity (> 70%) in cyclooxygenase (COX‐1 and COX‐2) assays at a 0.25 µg/μL concentration. Most of the extracts showed broad‐spectrum inhibitory and lethal activities against the microorganisms used in this study. The observed biological activities might be due to the iridoid, phenolic and flavonoid contents of the plants. Copyright © 2011 John Wiley & Sons, Ltd.     

天然间苯三酚类成分抗菌活性研究进展

抗菌药物的广泛使用甚至滥用使得细菌的耐药性日趋严重,耐药菌感染已成为威胁全球公共健康的重大问题。间苯三酚类成分广泛分布于陆地植物及海洋生物中,该类成分结构新颖、生物活性多样,其中不乏抗菌活性显著的新颖化合物,具有良好的开发前景。具有抗菌活性的天然间苯三酚类成分主要分布在桃金娘科及藤黄科植物中,该类成分对金黄色葡萄球菌及其耐药菌株、枯草芽孢杆菌、肠球菌等革兰阳性菌具有良好的抗菌效果。对近30年来报道的230个间苯三酚类成分的抗菌活性研究进行综述,以期为该类成分进一步研究和开发提供参考。     

Isolation and characterization of a new hispolone derivative from antioxidant extracts of Pistacia atlantica

The quantification of the total phenolic compounds of Pistacia atlantica showed that the different parts of the tree are rich in natural phenolic compounds. The antioxidant tests proved that the phenolic extracts have a strong antioxidant activity. The positive correlation between the Trolox equivalent antioxidant capacity (TEAC) and the amount of phenolic compounds confirms their contribution to the antioxidant activity. Among the various phenolic compounds isolated and characterized by spectroscopic methods, a new natural antioxidant 1 (methyl 5‐(3,4‐dihydroxyphenyl)‐3‐hydroxypenta‐2,4‐dienoate) derived from hispolone 2 has been isolated from the mushroom Inonotus hispidus growing on Pistacia atlantica. Hispolone 2 (6‐(3,4‐dihydroxyphenyl)‐4‐hydroxyhexa‐3,5‐dien‐2‐one) and hispidin 3 (6‐(2‐(3,4‐dihydroxyphenyl)vinyl)‐4‐hydroxy‐2H‐pyran‐2‐one) have been also identified using spectroscopic methods, including 2D‐NMR and EI‐MS. Copyright © 2009 John Wiley & Sons, Ltd.     

Antibacterial activity of flavonoids from the stem bark of Erythrina caffra thunb.

The antibacterial activity of the stem bark of Erythrina caffra Thunb. was investigated against different bacterial strains. The antibacterial activity was determined by a micro broth dilution assay. Antibacterial compounds were isolated and identified using a Bruker Avance III LPO NMR spectrometer. Four known flavonoids, abyssione‐V 4′‐O‐methyl ether, 6,8‐diprenylgenistein, alpinumisoflavone and burttinone, were isolated. All the compounds were active against both Gram‐negative and Gram‐positive bacteria. The minimum inhibitory concentration values obtained (MIC) ranged from 3.9 μg/mL to 125 μg/mL. This is the first report of antibacterial activity of burttinone and the isolation of these compounds from E. caffra. Copyright © 2010 John Wiley & Sons, Ltd.     

Anti‐Salmonella Activity of Volatile Compounds of Vietnam Coriander

Essential oil derived from the fresh leaves of Polygonum odoratum Lour was tested for their effects on a foodborne bacterium Salmonella choleraesuis subsp. choleraesuis ATCC 35640 using a broth dilution method. This essential oil showed a significant antibacterial activity against S. choleraesuis at the concentration of 200 µg/mL. Twenty‐five volatile compounds were characterized from this essential oil by GC‐MS, and aldehyde compounds were found abundant and accounted for more than three‐fourths of the essential oil. Among the compounds characterized, dodecanal (C₁₂) was the most abundant (55.5%), followed by decanal (C₁₀) (11.6%). Both alkanals were effective against S. choleraesuis with the minimum growth inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values of 100 µg/mL. The most potent antibacterial activity against this bacterium was found with two minor compounds, dodecanol (lauryl alcohol) and 2E‐dodecenal, both with each MBC of 6.25 µg/mL. Their primary antibacterial action against S. choleraesuis provably comes from their ability to function as nonionic surface‐active agents (surfactants), disrupting the native function of integral membrane proteins nonspecifically. Thus, the antibacterial activity is mediated by biophysical processes. In the case of 2E‐alkenals, a biochemical mechanism is also somewhat involved, depending on their alkyl chain length. Copyright © 2015 John Wiley & Sons, Ltd.     

Anti‐leishmanial Activities of Extracts and Isolated Compounds from Drechslera rostrata and Eurotium tonpholium

The fungal extract of Drechslera rostrata and Eurotium tonpholium showed a significant anti‐leishmanial activity against Leishmania major; IC₅₀ was 28.8 and 28.2 μg/mL, respectively. Seven compounds, five from D. rostrata (H1–H5) and two from E. tonpholium (H6 and H7), were isolated and identified using different spectroscopic analysis including ¹HNMR, ¹³CNMR, Hetero‐nuclear multiple bond connectivity (HMBC), Hetero‐nuclear Multiple Quantum Correlation (HMQC), and EI‐MS. The isolated compounds are: di‐2‐ethylhexyl phthalate (1), (22E)‐5α,8α‐epidioxyergosta‐6,22‐diene‐3β‐ol (2),1,3,8‐trihydroxy‐6‐methyl‐nthraquinone (3), aloe‐emodine 8‐O‐glucopyranoside(4), 2R, 3R,4R,5R hexane 1, 2, 3, 4, 5, 6 hexole (Mannitol) (5), 1,8‐dihydroxy‐3‐methoxy‐6‐methyl‐anthraquinone (6) and 1, 4, 5‐trihydroxy‐7‐methoxy‐2‐methyl‐anthraquinone (7). However, compounds (1) and (6) showed activity against L. major with IC₅₀ of 3.2 and 10.38 µg/mL, respectively. On the other hand, oral administration of the two extracts (100 mg/kg) and compounds 1 and 6 (50 mg/kg) showed very good activity when compared with the anti‐leishmanial drug Pentostam (125 mg/kg). Interestingly, the complete heeling activity of the extracts and compounds (1) and (6) was obtained after 13–17 days of treatment, while complete healing activity of Pentostam was obtained after 28 days. No alteration on liver and kidney functions was recorded on animals treated with the two extracts for 15 consecutive days. Copyright © 2013 John Wiley & Sons, Ltd.     

Two New Xanthones from Hypericum sampsonii and biological activity of the isolated compounds

Phytochemical investigation of the CH₂Cl₂ extract of the aerial part of Hypericum sampsonii yielded two new prenylated xanthones, hypericumxanthone A and B, together with three known xanthones. Their structures were elucidated by analysis of physical and spectral (UV, IR, mass and NMR) data and comparison of spectroscopic data with those reported previously. All these compounds were evaluated for in vitro antibacterial activity against methicillin‐resistant Staphylococcus aureus (MRSA). Two new compounds were also tested for their cytotoxicity against human breast (MCF‐7), hepatoma (HepG2), colon (HT‐29) and lung (A549) tumour cell lines. Two new compounds showed moderate antibacterial activities at minimum inhibitory concentrations (MIC) of 16 and 32 µg/mL, respectively, whereas the positive standard antibacterial drug, vancomycin, showed an MIC of 8 µg/mL. The other compounds were inactive against MRSA. In addition, hypericumxanthone B showed weak inhibitory activities against four human tumour cell lines. Copyright © 2010 John Wiley & Sons, Ltd.     

Antibacterial constituents from the rhizomes of Ferula communis

The rhizomes of Ferula communis yielded three antibacterial sesquiterpenes, namely, the new daucane ester 14-(o-hydroxycinnamoyloxy)-dauc-4,8-diene ( 1 ), ferulenol ( 2 ) and ferchromone ( 3 ). Compound 1 exhibited significant activity against Gram-positive bacteria, while 3 was found to be less active. Compound 2 , on the other hand, demonstrated potent activity against Mycobacterium organisms, and its corresponding C-4-acetoxy derivative 9 was found to retain the same activity as well. In addition, the rhizomes yielded a number of inactive compounds, including 2-nor-1,2-secoferulenol, elemicin, colladonin, feselol and compounds 4 and 5 . Structural assignments were largely based on the spectral data, especially the 2D NMR COSY and HETCOR experiments. © 1998 John Wiley & Sons, Ltd.