Bioactive compounds from Caulerpa racemosa as a potent larvicidal and antibacterial agent

Marine algae are rich sources ofbioactive compounds capable of harboring secondary metabolites which are structurally and biologically active. In our study, the methanolic extract of marine algae Caulerpa racemosa （green algae） was employed to determine the antibacterial and larvicidal activity. The antibacterial activity showed effective inhibition against five pathogenic bacteria. A significant zone size of 16 mm was observed for Pseudomonas aeruginosa. The methanolic extract of Caulerpa racemosa showed effective larvicidal activity against Culex tritaeniorhynchus and the histopathological studies revealed the rupture in mid gut of larvae. The bioactive compounds in the crude extract were further identified as 2-（-3-bromo-1-adamantyl） acetic acid methyl ester and Chola-5, 22- dien-3-ol by GC-MS. Hence the bioactive compounds obtained from the methanolic extracts could be used for the bactericidal and larvicidal activity which will overcome the harmful impact of synthetic insecticide on environment.     

Chemo-profiling of bioactive metabolites from Chaetomium globosum for biocontrol of Sclerotinia rot and plant growth promotion

Chaetomium globosum Kunze ex. Fries has been known to produce diverse bioactive metabolites, attracting researchers to exploit the biocontrol agent for plant disease management. However, distinct research gaps are visible regarding detail characterization of bioactive metabolites. Thus the current study has been planned to characterize volatile and nonvolatile compounds of most potential strain of C. globosum 5157. GC–MS analysis of hexane fraction revealed twenty-six volatile organic compounds, representing 65.5% of total components in which 3-octanone (21.4%) was found to be most abundant. UPLC-QTOF-MS/MS analysis of ethyl acetate and methanolic fractions resulted tentative characterization of fifteen and eleven metabolites, respectively. Among these, nine metabolites were isolated, purified and characterized using ¹H NMR and High resolution mass spectrometric analysis to delineate mass fragmentation pattern for the first time. Antifungal potential of hexane fraction exhibited high inhibitory action against Sclerotium rolfsii (139.2 μg mL^?1) whereas ethyl acetate fraction was highly effective against Sclerotinia sclerotiorum (112.1 μg mL^?1). Comparative assessment of C. globosum 5157 vis a vis Trichoderma harzianum A28 revealed promising effect of C. globosum 5157 with respect to antifungal properties and plant growth promotion of Brassica seedlings.     

Discovery of a new diol-containing polyketide by heterologous expression of a silent biosynthetic gene cluster from <Emphasis Type="Italic">Streptomyces lavendulae</Emphasis> FRI-5

The genome of streptomycetes has the ability to produce many novel and potentially useful bioactive compounds, but most of which are not produced under standard laboratory cultivation conditions and are referred to as silent/cryptic secondary metabolites. Streptomyces lavendulae FRI-5 produces several types of bioactive compounds. However, this strain may also have the potential to biosynthesize more useful secondary metabolites. Here, we activated a silent biosynthetic gene cluster of an uncharacterized compound from S. lavendulae FRI-5 using heterologous expression. The engineered strain carrying the silent gene cluster produced compound 5, which was undetectable in the culture broth of S. lavendulae FRI-5. Using various spectroscopic analyses, we elucidated the chemical structure of compound 5 (named lavendiol) as a new diol-containing polyketide. The proposed assembly line of lavendiol shows a unique biosynthetic mechanism for polyketide compounds. The results of this study suggest the possibility of discovering more silent useful compounds from streptomycetes by genome mining and heterologous expression.     

Roles of in vitro plantlet age and growing period in the phenolic constituent yields of acclimatized Hypericum polyanthemum

The influences of culture period on growth, plant survival rate and content of phenolic compounds were investigated in vitro and in acclimatized field-grown plants of Hypericum polyanthemum. The growth kinetics of micropropagated plantlets cultured in MS modified medium and the concomitant transference to ex vitro conditions showed that cultures achieved maximum biomass and yield of bioactive compounds after 12 weeks of in vitro growth, with field-grown plants displaying the same survival pattern. Differences in yield among plants cultured in vitro for 8 and 12 weeks that were acclimatized and followed over two years showed that the physiological age of the in vitro cultures influenced biomass production. However, benzopyrans and total phenolic compounds (TPC) contents did not vary significantly, with the exception of the 5-hydroxy-6-isobutyryl-7-methoxy-2,2-dimethyl-benzopyran (HP3) concentration in the reproductive parts, which was higher in the plants grown in vitro for 12 weeks over the two years of the study. All analyzed plant parts from the spring harvest accumulated lower benzopyran levels than plants harvested after 18 weeks of growth in both treatments, except for the levels of 6-isobutyryl-5,7-dimethoxy-2,2-dimethyl-benzopyran (HP1) and 7-hydroxy-6-isobutyryl-5-methoxy-2,2-dimethyl-benzopyran (HP2) in the new vegetative parts of the plants, which did not vary. The concentration of TPC, which was detected at low levels in the old vegetative parts in both treatments, was not altered in other plant parts. The information provided by this work will help structure plant growth and collection periods designed to optimize the yield of each required bioactive metabolite.     

Unveiling antimicrobial activity of microalgae Chlorella sorokiniana (UKM2), Chlorella sp. (UKM8) and Scenedesmus sp. (UKM9)

Microalgae represent promising sources of bioactive compounds for pharmaceutical and industrial applications. The emergence of antibiotic resistant bacteria leads to the need to explore new cost-effective, safe, and potent bioactive compounds from the microalgae. This study aimed to investigate the potential of local microalgae for their antimicrobial properties and bioactive compounds. Three local microalgae namely Chlorella sorokiniana (UKM2), Chlorella sp. UKM8, and Scenedesmus sp. UKM9 biomass methanol extracts (ME) were prepared and tested against Gram-positive and Gram-negative bacteria. Chlorella sp. UKM8-ME showed the highest antibacterial activity. UKM8-ME minimum inhibitory concentrations were in the range of 0.312 to 6.25 mg/mL. Cytotoxicity evaluation using MTT assay showed that the microalgae methanolic extracts did not exhibit cytotoxicity against Vero-cells. The UKM8-ME was mainly containing 28 compounds from the Gas Chromatography-Mass Spectrometry (GC–MS) analysis. Major compounds of UKM8-ME included phenol (18.5%), hexadecanoic acid (18.25%), phytol (14.43%), 9,12-octadecadienoic acid (13.69%), and bicyclo[3.1.1]heptane (7.23%), which have been previously described to possess antimicrobial activity. Hence, Chlorella sp. (UKM8) methanol extracts showed promising antibacterial activity. More comprehensive studies are required to purify these antimicrobial compounds and develop our understanding on their mechanism in UKM8-ME to unleash their specific potential.     

Influence of fungal elicitation with Nomuraea rileyi (Farlow) Samson in the metabolism of acclimatized plants of Hypericum polyanthemum Klotzsech ex Reichardt (Guttiferae)

Changes in biomass and bioactive metabolites after treatment with the fungus Nomuraea rileyi (Farlow) Samson added as dried culture (DC) or as dried autoclaved cell powder (DACP) for short and long periods of time have been investigated in Hypericum polyanthemum plants grown under controlled conditions and after 18 weeks of field acclimatization. Plants grown under controlled conditions and treated with DACP showed increased concentrations of the benzopyrans HP1 (6-isobutyryl-5,7-dimethoxy-2,2-dimethylbenzopyran), HP2 (7-hydroxy-6-isobutyryl-5-methoxy-2,2-dimethylbenzopyran), and HP3 (5-hydroxy-6-isobutyryl-7-methoxy-2,2-dimethylbenzopyran) while DC affected negatively or did not alter the synthesis of these compounds. Lower levels of the phloroglucinol derivative uliginosin B were detected in all treatments. Long time treatment with DACP of acclimatized plants triggered doubling of biomass as compared to control and chemical analyses demonstrated significant increase on total phenolic compounds in vegetative parts of plants. Moreover, the higher performance liquid chromatography analysis showed different pattern of metabolites accumulation, with higher yields of HP1, HP2, HP3 and uliginosin B in the reproductive parts of the plants treated with DACP during all experiments. The elevation of bioactive metabolites levels in response to the elicitor suggests that these compounds are inducible as part of the defense response of H. polyanthemum.     

The bioactive alkaloids identified from Cortex Phellodendri ameliorate benign prostatic hyperplasia via LOX-5/COX-2 pathways

BackgroundThe bioactive alkaloids identified from Cortex Phellodendri (CP) were highly effective in treating rats with benign prostatic hyperplasia (BPH). Specifically, lipoxygenase-5 (LOX-5) and cyclooxygenase-2 (COX-2) were identified as two primary targets for alleviating inflammation in BPH rats. However, it remains unknown whether the alkaloid components in CP can interact with the two target proteins.PurposeTo further identify bioactive alkaloids targeting LOX/COX pathways.MethodsAn affinity-ultrafiltration mass spectrometry approach was employed to screen dual-target LOX-5/COX-2 ligands from alkaloid extract. The structures of bioactive alkaloids were characterized by high-resolution Fourier transform ion cyclotron resonance mass spectrometry. To understand the molecular mechanisms underlying the effects of bioactive alkaloids, the expression levels of LOX-5 and COX-2 in BPH model rats were investigated at both protein and mRNA levels. The LOX-5/COX-2 enzymes activity experiments and molecular docking analysis were performed to fully evaluate the interactions between bioactive alkaloids and LOX-5/COX-2.ResultsAfter comprehensive analysis, the results showed that bioactive alkaloids could suppress the expression of LOX-5 and COX-2 simultaneously to exert an anti-inflammatory effect on the progression of BPH. In addition, the screened protoberberine, demethyleneberberine was found to exhibit prominent inhibitory activities against both LOX-5 and COX-2 enzymes, palmatine and berberine with moderate inhibitory activities. Molecular docking analysis confirmed that demethyleneberberine could interact well with LOX-5/COX-2.ConclusionThis study is the first to explore the inhibitory effects of bioactive alkaloids from CP on LOX-5 and COX-2 activities in BPH rats. Our findings demonstrate that the bioactive alkaloids from CP can ameliorate BPH via dual LOX-5/COX-2 pathways, which serves as an efficient approach for the discovery of novel drug leads from natural products with reduced side effects.     

Antifouling activities expressed by marine surface associated Pseudoalteromonas species

Members of the marine bacterial genus Pseudoalteromonas have been found in association with living surfaces and are suggested to produce bioactive compounds against settlement of algal spores, invertebrate larvae, bacteria and fungi. To determine the extent by which these antifouling activities and the production of bioactive compounds are distributed amongst the members of the genus Pseudoalteromonas, 10 different Pseudoalteromonas species mostly derived from different host organisms were tested in a broad range of biofouling bioassays. These assays included the settlement of larvae of two ubiquitous invertebrates Hydroides elegans and Balanus amphitrite as well as the settlement of spores of the common fouling algae Ulva lactuca and Polysiphonia sp. The growth of bacteria and fungi, which are the initial fouling organisms on marine surfaces, was also assayed in the presence of each of the 10 Pseudoalteromonas species. It was found that most members of this genus produced a variety of bioactive compounds. The broadest range of inhibitory activities was expressed by Pseudoalteromonas tunicata which inhibited all target fouling organisms. Only two species, Pseudoalteromonas haloplanktis and Pseudoalteromonas nigrifaciens, displayed negligible activity in the bioassays. These were also the only two non-pigmented species tested in this study which indicates a correlation between production of bioactive compounds and expression of pigment. Three members, P. tunicata, Pseudoalteromonas citrea and Pseudoalteromonas rubra, were demonstrated to express autoinhibitory activity. It is suggested that most Pseudoalteromonas species are efficient producers of antifouling agents and that the production of inhibitory compounds by surface associated Pseudoalteromonas species may aid the host against colonisation of its surface.     

Phytochemicals with NO inhibitory effects and interactions with iNOS protein from Trigonostemon howii

A phytochemical investigation to obtain new NO inhibitors led to the isolation of nine compounds including one new guaiane-type sesquiterpenoid (1) and two new cleistanthane diterpenoids (2 and 3) from the stems of Trigonostemon howii. Their structures were elucidated on the basis of extensive 1D and 2D NMR spectroscopic data analysis, and the absolute configurations of new compounds 1–3 were established via comparison of experimental and calculated electronic circular dichroism (ECD) spectra. Compounds 2 and 3 possess a rare 3,4-seco-cleistanthane diterpenoid skeleton. All of the compounds showed inhibitory effects on lipopolysaccharide-induced NO production in murine microglial BV-2 cells. The further molecular docking studies indicated the strong interactions between some bioactive compounds with the iNOS protein, which revealed the possible and potential mechanism of NO inhibition of bioactive compounds.     

Biochemical evaluation and molecular docking assessment of Cymbopogon citratus as a natural source of acetylcholine esterase (AChE)- targeting insecticides

Acetylcholinesterase (AChE) has been an effective target for insecticide development which is a very important aspect of the global fight against insect-borne diseases. The drastic reduction in the sensitivity of insects to AChE-targeting insecticides like organophosphates and carbamates have increased the need for insecticides of natural origin. In this study, we used Drosophila melanogaster as a model to investigate the insecticidal and AChE inhibitory potentials of Cymbopogon citratus and its bioactive compounds. Flies were exposed to 100 and 200 mg/mL C. citratus leaf extract for a 3-h survival assay followed by 45 min exposure for negative geotaxis and biochemical assays. Molecular docking analysis of 45 bioactive compounds of the plant was conducted against Drosophila melanogaster AChE (DmAChE). Exposure to C. citratus significantly reduced the survival rate of flies throughout the exposure period and this was accompanied by a significant decrease in percentage negative geotaxis, AChE activity, catalase activity, total thiol level and a significant increase in glutathione-S-transferase (GST) activity. The bioactive compounds of C. citratus showed varying levels of binding affinities for the enzyme. (+)-Cymbodiacetal scored highest (?9.407 kcal/mol) followed by proximadiol (?8.253 kcal/mol), geranylacetone (?8.177 kcal/mol), and rutin (?8.148 kcal/mol). The four compounds occupied the same binding pocket and interacted with important active site amino acid residues as the co-crystallized ligand (1qon). These compounds could be responsible for the insecticidal and AChE inhibitory potentials of C. citratus and they could be further explored in the development of AChE-targeting insecticides.     

Natural products of Alternaria sp., an endophytic fungus isolated from Salvadora persica from Saudi Arabia

This study is to evaluate the potential of endophytic fungi of Salvadora persica for the production of bioactive compounds against pathogenic bacteria and fungi. Forty-two fungal isolates were obtained from 135 young and old stem and 125 root segments. Those 42 isolates representing ten fungi include: Trichoderma sp. (the most common), two species of Alternaria, Rhizopus arrhizus and 6 sterile mycelia. The ten fungi were grown in liquid culture and their crude extracts were tested against pathogenic bacteria and fungi. Nine crude extracts gave positive reactions against pathogenic bacteria of which Alternaria sp. (A8) was chosen further study. The fungal isolate was growing as sterile mycelium and was identified by phylogenetic analyses based on LSU rDNA sequence data and it might represent undescribed species of Alternaria. Sixty-two bioactive chemical compounds were identified from the ethyl acetate crude extracts of Alternaria sp., of which the following were recorded as major compounds in the active sub-fractions. These compounds showed strong antibacterial activity in combination.     

Antifungal and cytotoxic activities of the secondary metabolites from endophytic fungus Massrison sp.

Three novel compounds with spiro-5, 6-lactone ring skeleton has been isolated from the fermentation broth of Massrison sp. which could be isolated repeatedly from wild Rehmannia glutinosa. Psetariae oryza P-2b was applied to guide fractionation of bioactive compounds produced by Massrison sp. The molecular structures were established by a variety of one- and two-dimensional NMR experiments and the compounds with similar skeleton were reported for the first time from endophytic fungi of terraneous plant. Antifungal and cytotoxic activities of the compounds were tested, compounds 2 and 3 displayed stronger antifungal and cytotoxic activities. The compounds have the potential to be antibiotic against fungal pathogens and tumor cells.     

FT-IR and GC-MS analyses of potential bioactive compounds of cow urine and its antibacterial activity

The main emphasis of this study was to identify the bioactive compounds responsible for antibacterial activity of Badri cow urine isolated by thin layer chromatography. The most effective bioactive fraction was analysed by FT-IR and GC-MS analyses. Among the four major fractions (EW1, EW2, CA1 and CA2) obtained by TLC profiling, EW1 was found most active against bacterial strains viz., Listeria monocytogenes (MTCC657), Staphylococcus aureus (MTCC7443), Pseudomonas aeruginosa (MTCC424), Klebsiella pneumoniae (MTCC432) and Salmonella typhi (MTCC733). However, Escherichia coli (MTCC118), was found resistant to all the fractions. In FT-IR spectroscopy, functional groups like alcohol, amide, alkene, alkyl halide, polysulfide and phosphate ions were identified. The GC-MS analysis of EW1 fraction exhibited the presence of 12 compounds, of which 1-heneicosanol was found as the major compound. These compounds might be responsible synergistically or individually for antibacterial activity of cow urine. Nine elements namely sodium (Na), calcium (Ca), chromium (Cr), iron (Fe), magnesium (Mg), aluminium (Al), potassium (K) and zinc (Zn), Gold (Au) were measured by ICP-MS analysis.     

Penicillium verruculosum SG: a source of polyketide and bioactive compounds with varying cytotoxic activities against normal and cancer lines

A newly isolated fungus Penicillium verruculosum SG was evaluated for the production and characterization of bioactive colored secondary metabolites using solid-state fermentation along with their cytotoxic activities against normal and cancer cell lines. Logical fragmentation pattern following column chromatography, thin layer chromatography and liquid chromatography and mass spectrometry of crude culture filtrate of fungus revealed the presence of different polyketide pigments and other bioactive compounds. Cytotoxicity of the selected colored fractions of fungal filtrate containing different compounds revealed IC50 (μg/ml) values ranging from 5 to 100. It was significantly higher in case of orevactaene (5 + 0.44) and monascorubrine followed by pyripyropene (8 + 0.63) against cancer cell line KA3IT. Overall, these compounds considerably showed less toxicity toward normal cell lines NIH3T3, HSCT6, HEK293 and MDCK. XRD of a yellow crystalline compound (224.21 m/z) confirmed its 3-dimensional structure as phenazine 1 carboxylic acid (C13H8N2O2) (broad spectrum antibiotic), and it is first time reported in fungi.     

Citrus bioactive compounds improve bone quality and plasma antioxidant activity in orchidectomized rats

BackgroundsWe reported that citrus consumption improves bone quality in orchidectomized male rats. In the present study, effects of feeding citrus bioactive compounds and crude extract on bone quality in orchidectomized rats were evaluated.MethodsSeventy 90-days-old male rats were randomly assigned to five groups for 60 days of feeding study. The treatment groups were SHAM-control, orchidectomy (ORX), ORX+crude extract, ORX+limonin, and ORX+naringin. At termination, animals were euthanized, blood was collected for the plasma antioxidant status. Bone resorption and bone formation markers in the blood and urine were evaluated. Bone quality in the femur and the 5th lumbar and the total calcium concentration in the bones and excreta were evaluated.ResultsOrchidectomy lowered (p<0.05) plasma antioxidant capacity, bone quality, and bone calcium; elevated (p<0.05) TRAP, deoxypyridinoline (DPD), and calcium excretion; and did not change the plasma IGF-I in comparison to the SHAM group. The citrus crude extract or the purified bioactive compounds increased (p<0.05) the plasma antioxidant status, plasma IGF-I, and bone density, preserved (p<0.05) the concentration of calcium in the femur and in the 5th lumbar, and numerically improved bone strength. The crude extract and the bioactive compounds decreased (p<0.05) fecal excretion of calcium, numerically lowered the urinary excretion of calcium, and suppressed (p<0.05) the plasma TRAP activity without affecting (p>0.1) urinary excretion of DPD in comparison to the ORX group.ConclusionsPotential benefit of the citrus crude extract and its bioactive compounds on bone quality appears to preserve bone calcium concentration and increase antioxidant status.     

Chemical defenses of tunicates of the genus Aplidium from the Weddell Sea (Antarctica)

Predation and competition are important factors structuring Antarctic benthic communities and are expected to promote the production of chemical defenses. Tunicates are subject to little predation, and this is often attributed to chemical compounds, although their defensive activity has been poorly demonstrated against sympatric predators. In fact, these animals, particularly the genus Aplidium, are rich sources of bioactive metabolites. In this study, we report the natural products, distribution and ecological activity of two Aplidium ascidian species from the Weddell Sea (Antarctica). In our investigation, organic extracts obtained from external and internal tissues of specimens of A. falklandicum demonstrated to contain deterrent agents that caused repellency against the Antarctic omnivorous predator, the sea star Odontaster validus. Chemical analysis performed with Antarctic colonial ascidians Aplidium meridianum and Aplidium falklandicum allowed the purification of a group of known bioactive indole alkaloids, meridianins A-G. These isolated compounds proved to be responsible for the deterrent activity.     

Evaluation of bioactive compounds,free radical scavenging and anticancer activities of bulb extracts of Boophone disticha from Eastern Cape Province,South Africa

Boophone disticha (B. disticha) is a bulbous tropical and subtropical flowering plant widespread in Africa, which is frequently used to treat several human ailments. Until the present, there is no scientific validation on the biological activity of this plant from the Eastern Cape Province of South Africa and as a result, this study aimed to assess the bioactive compounds, free radicals scavenging and anticancer potentials of crude bulb extracts (chloroform, acetone, and ethanol) of Boophone disticha obtained from this geographical location. Standard biochemical techniques and Gas-chromatography mass spectrometry (GCMS) analysis were used to pinpoint the bioactive compounds in the crude extracts sequel to their antioxidant potentials against radicals such as 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), hydrogen peroxide and nitric oxide as well as their ferric ion reducing power. In addition, their cytotoxicity effects against Human cervix adenocarcinoma (HeLa) cells were assessed as an in vitro model for anticancer. The phytochemical evaluation of the crude extracts showed the presence of phenolics, flavonoids, and alkaloids. GCMS profiles confirmed the presence of some bioactive compounds in the crude extracts of B. disticha that could be responsible for their biological activities. The plant extracts possessed considerable antioxidant activity and exhibited dose-dependent radicals’ inhibition from all assays carried out. Furthermore, the cytotoxicity effects against HeLa cells recorded inhibition concentration (IC₅₀) of 1.5, 1.6, and 1.9 µg/mL for acetone, chloroform, and ethanolic extracts of B. disticha, respectively. Findings from the present study suggest that B. disticha could be a good prospective source of antioxidant and anticancer agents. Therefore, further research on the isolation and purification of compounds from these extracts are indispensable.     

Analysis of bioactive compounds and chemical composition of Malaysian stingless bee propolis water extracts

Propolis is a resinous substance collected by stingless bees containing bioactive compounds which exert various biological properties. The present study focused on the evaluation of chemical profiles produced by three Indo-Malayan stingless bee propolis extracted using water. Fresh propolis was collected from the same area and ecosystem conditions in Selangor, Malaysia, namely Tetrigona apicalis, Tetrigona binghami, and Heterotrigona fimbriata. The bioactive compounds and chemical composition of propolis extracts were then analyzed using gas chromatography–mass spectrometry (GC–MS). Results showed that propolis from the three different stingless bee species consisted of major groups such as sugar (31.4%), carboxylic acid (17.1%), terpenoid (14.3%), sugar alcohol (11.4%), hydrocarbon (5.7%), aldehyde (5.7%) amino acid (2.9%) and other constituents (11.4%). Heterotrigona fimbriata displayed the highest amount for both total phenolics (13.21 mg/mL) and flavonoids (34.53 mg/mL) compared to other propolis extracts. There is also no significant difference detected between all samples since p ≤ 0.05. In conclusion, this study shows that Malaysian stingless bee propolis contain bioactive components that have great potential to be used for their therapeutic and medicinal benefits. However, more investigations and analysis of stingless bee propolis need to be carried out in order to enhance the understanding and applications of propolis in the future.