Isolation, Structure Determination, and Total Synthesis of Hoshinoamide C, an Antiparasitic Lipopeptide from the Marine Cyanobacterium Caldora penicillata

Hoshinoamide C (1), an antiparasitic lipopeptide, was isolated from the marine cyanobacterium Caldora penicillata. Its planar structure was elucidated by spectral analyses, mainly 2D NMR, and the absolute configurations of the α-amino acid moieties were determined by degradation reactions followed by chiral-phase HPLC analyses. To clarify the absolute configuration of an unusual amino acid moiety, we synthesized two possible diastereomers of hoshinoamide C and determined its absolute configuration based on a comparison of their spectroscopic data with those of the natural compound. Hoshinoamide C (1) did not exhibit any cytotoxicity against HeLa or HL60 cells at 10 μM, but inhibited the growth of the parasites responsible for malaria (IC₅₀ 0.96 μM) and African sleeping sickness (IC₅₀ 2.9 μM).

Allelopathic Potential and Active Substances from Wedelia Chinensis (Osbeck)

Wedelia chinensis (Asteraceae) is a wetland herb native to India, China, and Japan. It is a valuable medicinal plant recorded to have pharmaceutical properties. However, the phytotoxic potential of Wedelia chinensis has not yet been examined. Thus, we carried out this study to establish the allelopathic effects of Wedelia chinensis and to identify its phytotoxic substances. Extracts of Wedelia chinensis exhibited high inhibitory activity against the root and shoot growth of cress, alfalfa, rapeseed, lettuce, foxtail fescue, Italian ryegrass, timothy, and barnyard grass. The inhibition was varied with species and was dependent on concentrations. The extracts were separated through several purification steps, and the two effective substances were isolated and characterized as vanillic acid and gallic acid using spectral analysis. Vanillic acid and gallic acid significantly arrested the growth of cress and Italian ryegrass seedlings. The concentrations of vanillic acid and gallic acid needed for 50% inhibition (I₅₀ values) of the seedling growth of the cress and Italian ryegrass were 0.04–15.4 and 0.45–6.6 mM, respectively. The findings suggest that vanillic acid and gallic acid may be required for the growth inhibitory activities of Wedelia chinensis.

Dactylospenes A-E, Sesterterpenes from the Marine Sponge Dactylospongia elegans

Chemical investigation on a marine sponge, Dactylospongia elegans, yielded five new γ-oxygenated butenolide sesterterpene derivatives, dactylospenes A–E (1–5), as well as two known biosynthetically related compounds, luffariellolide (6) and furospinosulin B (7). The structures of these compounds were elucidated on the basis of their spectroscopic data, experimental and calculated electronic circular dichroism (ECD) analysis, as well as comparison of the NMR data with those of known analogs. These metabolites are the first γ-oxygenated butenolide sesterterpenes to be reported from this genus. These compounds were evaluated in antimicrobial, anti-inflammatory, and cytotoxic assays. Only compounds 1, 3, and 6 exhibited moderate cytotoxicity against DU145, SW1990, Huh7, and PANC-1 cancer cell lines with IC₅₀ values in the range of 2.11–13.35 μM. Furthermore, compound 2, without cytotoxicity, exhibited significant inhibitory effects (inhibitory rate 77.5%) on nitric oxide production induced by lipopolysaccharide at 10 μM.

Potential use of Schumannianthus dichotomus waste: the phytotoxic activity of the waste and its identified compounds

The phytotoxic potential of the leaves and twigs of Schumannianthus dichotomus, discarded in the mat-making industry against four test plants (lettuce (Lactuca sativa L.), rapeseed (Brassica napus L.), foxtail fescue (Vulpia myuros (L.) C.C. Gmel.) and timothy (Phleum pratense L.)) was investigated and found strong phytotoxic activity. An assay-guided fractionation of S. dichotomus extarcts against cress (Lepidium sativum L.) through a series of column chromatography steps yielded two compounds, 8-(5-oxo-2,5-dihydrofuran-2-yl) octanoic acid (ODFO) and (E)-6-hydroxy-2,6-dimethylocta-2,7-dienoic acid (8-carboxylinalool). ODFO and 8-carboxylinalool showed strong phytotoxic activity against cress and timothy. The concentrations required for 50% growth inhibition (I50 value) of the seedlings of cress and timothy were 111.94-128.01 and 36.30-91.75 µM, respectively, for ODFO, but the values were much higher at 315.98-379.13 and 107.92-148.41 µM, respectively, for 8-carboxylinalool, indicating the stronger phytotoxic activity of ODFO. This study is the first to isolate ODFO and 8-carboxylinalool from S. dichotomus and their phytotoxic potential while ODFO is firstly encountered from any natural source. The growth inhibitory activity of the identified compounds may explain their role in the phytotoxic activity of S. dichotomus, which suggests the possible use of its leaves and twigs or its active constituents as natural bioherbicides.

Irijimasides A-E, Macrolide Glycosides from an Okeania sp. Marine Cyanobacterium

Irijimasides A-E (1-5), a series of new 14-membered macrolide glycosides, were isolated from a marine cyanobacterium collected in Okinawa. The gross structures of 1-5 were established by spectroscopic analysis, including 2D NMR, while absolute stereostructures were determined based on NOESY spectra, chemical derivatization, and ECD data. All five macrolides suppressed receptor activator of nuclear factor-κB ligand (RANKL)-induced tartrate-resistant acid phosphatase (TRAP) activity in mouse RAW264 macrophage cells, indicating that these compounds inhibit osteoclast formation.

Iheyamides A-C, Antitrypanosomal Linear Peptides Isolated from a Marine Dapis sp. Cyanobacterium

Iheyamides A (1), B (2), and C (3), new linear peptides, were isolated from a marine Dapis sp. cyanobacterium. Their structures were elucidated by spectroscopic analyses and degradation reactions. Iheyamide A (1) showed moderate antitrypanosomal activities against Trypanosoma brucei rhodesiense and Trypanosoma brucei brucei (IC₅₀ = 1.5 μM), but the other two analogues, iheyamides B (2) and C (3), did not (IC₅₀ > 20 μM, respectively). The structure-activity relationship clarified that an isopropyl-O-Me-pyrrolinone moiety was necessary for the antitrypanosomal activity. Furthermore, the cytotoxicity of 1 against normal human cells, WI-38, was 10 times weaker than its antitrypanosomal activity (IC₅₀ = 18 μM).

A comparative effectiveness pilot study of teriparatide for medication-related osteonecrosis of the jaw: daily versus weekly administration

We studied the effectiveness of teriparatide (TPTD) for treating medication-related osteonecrosis of the jaw (MRONJ) in patients with osteoporosis and examined differences in the clinical outcomes following daily versus weekly TPTD. The outcomes were significantly improved in the entire patient series and the daily group.

PURPOSE

Teriparatide (TPTD) treatment for Stage II-III medication-related osteonecrosis of the jaw (MRONJ) in osteoporotic patients has yielded promising results in uncontrolled studies. The daily administration and the weekly administration of TPTD have been reported to improve outcomes in MRONJ. Herein, we sought to identify differences in the clinical outcomes of MRONJ patients treated with daily TPTD versus weekly TPTD.

METHODS

We enrolled 13 patients and randomly assigned them to receive either of two treatments: 1×/week 56.5-μg TPTD injection for 6 months (weekly group; n = 6 patients after 1 dropout), or 20-μg TPTD injection daily for 6 months (daily group; n = 6 patients). Patients in both groups received conventional therapy plus intensive antibiotic therapy as necessary. We compared the changes in the patients' clinical stage of MRONJ, bone metabolism, percentage of bone formation, and bone turnover markers between the weekly and daily groups.

RESULTS

TPTD treatment with MRONJ led to partial remission or complete remission in 5 daily-group patients and 3 weekly-group patients. The MRONJ stage was significantly improved from baseline to 6 months of treatment in the entire series of 12 patients (p = 0.008); the weekly group did not show significant improvement, but the daily group did (p = 0.01).

CONCLUSIONS

This study provides the first comparison of clinical outcomes between MRONJ patients who received daily or weekly TPTD injections. Six months of treatment with TPTD realized a significant improvement of MRONJ stage in both the entire patient series and the daily group.

Ikoamide, an Antimalarial Lipopeptide from an Okeania sp. Marine Cyanobacterium

An antimalarial lipopeptide, ikoamide, was isolated from an Okeania sp. marine cyanobacterium. Its gross structure was established by spectroscopic analyses, and the absolute configuration was clarified based on a combination of chiral-phase HPLC analyses, spectroscopic analyses, and derivatization reactions. Ikoamide showed strong antimalarial activity with an IC₅₀ value of 0.14 μM without cytotoxicity against human cancer cell lines at 10 μM.

Tree Fern Cyathea lepifera May Survive by Its Phytotoxic Property

Cyatheaceae (tree ferns) appeared during the Jurassic period and some of the species still remain. Those species may have some morphological and/or physiological characteristics for survival. A tree fern was observed to suppress the growth of other ligneous plants in a tropical forest. It was assumed that the fern may release toxic substances into the forest floor, but those toxic substances have not yet been identified. Therefore, we investigated the phytotoxicity and phytotoxic substances of Cyathea lepifera (J. Sm. ex Hook.) Copel. An aqueous methanol extract of C. lepifera fronds inhibited the growth of roots and shoots of dicotyledonous garden cress (Lepidum sativum L.), lettuce (Lactuca sativa L.), and alfalfa (Medicago sativa L.), and monocotyledonous ryegrass (Lolium multiflorum Lam.), timothy (Phleum pratense L.), and barnyardgrass (Echinochloa crus-galli (L.) P. Beauv.). The results suggest that C. lepifera fronds may have phytotoxicity and contain some phytotoxic substances. The extract was purified through several chromatographic steps during which inhibitory activity was monitored, and p-coumaric acid and (-)-3-hydroxy-β-ionone were isolated. Those compounds showed phytotoxic activity and may contribute to the phytotoxic effects caused by the C. lepifera fronds. The fronds fall and accumulate on the forest floor through defoliation, and the compounds may be released into the forest soils through the decomposition process of the fronds. The phytotoxic activities of the compounds may be partly responsible for the fern's survival.

Estimating transboundary transported anthropogenic sulfate deposition in Japan using the sulfur isotopic ratio

High emissions of air pollutants from Northeast Asia are strongly influenced by air quality as well as by ecosystems. This study investigated the spatiotemporal variations in the sulfur isotopic ratio (δ³⁴S) in atmospheric deposition at eleven monitoring stations in Japan from 2011 to 2016 and estimated the amount of transboundary transported anthropogenic sulfate (TRB) deposition using mass balance calculations. The δ³⁴S of sulfate in precipitation ranged from -0.42 to +22.7‰. Sea salt (SS), TRB, and domestic anthropogenic sources (DOM) were the dominant sources of sulfate deposition in Japan. TRB sulfate deposition was largest on the Sea of Japan side, with an annual average value of 1.5 ± 0.3-6.9 ± 0.5 mg m^-2 d^-1 (36-44%), followed by Mt. Happo (4.5 ± 0.1 mg m^-2 d^-1; 88%), the Pacific Ocean side (1.5 ± 0.8, 4.3 ± 0.9 mg m^-2 d^-1; 24-50%), and the remote islands in the North Pacific Ocean (1.1 ± 0.2, 2.0 ± 0.8 mg m^-2 d^-1; 19-32%). TRB sulfate deposition on the Sea of Japan side was 2-12 times higher in winter and 1-2 times higher in summer than that of DOM. In contrast, TRB sulfate deposition on the Pacific Ocean side was 1.5-3 times higher in summer than in winter due to high precipitation levels. In Tokyo, the annual contribution from DOM sulfate deposition is approximately three times higher than that from TRB. Annual TRB sulfate deposition is lowest at Ogasawara at 1.1 ± 0.2 mg m^-2 d^-1, and the annual oceanic DMS contribution to sulfate deposition is high, accounting for 1.3 mg m^-2 d^-1 (20 ± 6%). The contribution of Asian dust was estimated to be 1-5.2 mg m^-2 d^-1(3-6%), which occurred in a single Asian dust event on the Sea of Japan side.

Isolation and Total Synthesis of Mabuniamide, a Lipopeptide from an Okeania sp. Marine Cyanobacterium

The bioassay-guided fractionation of an Okeania sp. marine cyanobacterium collected in Okinawa led to the isolation of the lipopeptide mabuniamide (1). The gross structure of 1 was determined by spectroscopic analyses, and its absolute configuration was determined using Marfey's analysis of the acid hydrolysate of 1. The absolute configuration of 1 was confirmed by total synthesis. Mabuniamide (1) stimulated glucose uptake in cultured rat L6 myotubes. In addition, mabuniamide (1) and its stereoisomer (2) exhibited moderate antimalarial activity.

Cytotoxic Microcolin Lipopeptides from the Marine Cyanobacterium Moorea producens

Nine new linear lipopeptides, microcolins E-M (1-9), together with four known related compounds, microcolins A-D (10-13), were isolated from the marine cyanobacterium Moorea producens using bioassay-guided and LC-MS/MS molecular networking approaches. Catalytic hydrogenation of microcolins A-D (10-13) yielded two known compounds, 3,4-dihydromicrocolins A and B (14, 15), and two new derivatives, 3,4-dihydromicrocolins C and D (16, 17), respectively. The structures of these new compounds were determined by a combination of spectroscopic and advanced Marfey's analysis. Structurally unusual amino acid units, 4-methyl-2-(methylamino)pent-3-enoic (Mpe) acid and 2-amino-4-methylhexanoic acid (N-Me-homoisoleucine), in compounds 1-3 and 8, respectively, are rare residues in naturally occurring peptides. These metabolites showed significant cytotoxic activity against H-460 human lung cancer cells with IC₅₀ values ranging from 6 nM to 5.0 μM. The variations in structure and attendant biological activities provided fresh insights concerning structure-activity relationships for the microcolin class of lipopeptides.

Garcienone, a Novel Compound Involved in Allelopathic Activity of Garcinia Xanthochymus Hook

Plants are sources of diversified allelopathic substances that can be investigated for use in eco-friendly and efficient herbicides. An aqueous methanol extract from the leaves of Garcinia xanthochymus exhibited strong inhibitory activity against barnyard grass (Echinochloa crus-galli (L.) P. Beauv.), foxtail fescue (Vulpia myuros (L.) C.C.), alfalfa (Medicago sativa L.), and cress (Lepidium sativum L.), and appears to be a promising source of allelopathic substances. Hence, bio-activity guided purification of the extract through a series of column chromatography steps yielded a novel compound assigned as garcienone ((R, E)-5-hydroxy-5-((6S, 9S)-6-methyl-9-(prop-13-en-10-yl) tetrahydrofuran-6-yl) pent-3-en-2-one). Garcienone significantly inhibited the growth of cress at a concentration of 10 μM. The concentrations resulting in 50% growth inhibition (I50) of cress roots and shoots were 120.5 and 156.3 μM, respectively. This report is the first to isolate and identify garcienone and to determine its allelopathic potential.

Marine Natural Products: A Source of Novel Anticancer Drugs

Cancer remains one of the most lethal diseases worldwide. There is an urgent need for new drugs with novel modes of action and thus considerable research has been conducted for new anticancer drugs from natural sources, especially plants, microbes and marine organisms. Marine populations represent reservoirs of novel bioactive metabolites with diverse groups of chemical structures. This review highlights the impact of marine organisms, with particular emphasis on marine plants, algae, bacteria, actinomycetes, fungi, sponges and soft corals. Anti-cancer effects of marine natural products in in vitro and in vivo studies were first introduced; their activity in the prevention of tumor formation and the related compound-induced apoptosis and cytotoxicities were tackled. The possible molecular mechanisms behind the biological effects are also presented. The review highlights the diversity of marine organisms, novel chemical structures, and chemical property space. Finally, therapeutic strategies and the present use of marine-derived components, its future direction and limitations are discussed.

Marine Natural Products: A Source of Novel Anticancer Drugs

Cancer remains one of the most lethal diseases worldwide. There is an urgent need for new drugs with novel modes of action and thus considerable research has been conducted for new anticancer drugs from natural sources, especially plants, microbes and marine organisms. Marine populations represent reservoirs of novel bioactive metabolites with diverse groups of chemical structures. This review highlights the impact of marine organisms, with particular emphasis on marine plants, algae, bacteria, actinomycetes, fungi, sponges and soft corals. Anti-cancer effects of marine natural products in in vitro and in vivo studies were first introduced; their activity in the prevention of tumor formation and the related compound-induced apoptosis and cytotoxicities were tackled. The possible molecular mechanisms behind the biological effects are also presented. The review highlights the diversity of marine organisms, novel chemical structures, and chemical property space. Finally, therapeutic strategies and the present use of marine-derived components, its future direction and limitations are discussed.

Phytotoxic activity of crop residues from Burdock and an active substance

Problems related to weed management such as outbreaks of herbicide-resistant weeds have recently increased. An interesting approach to such problems is to use plant materials with phytotoxic activity. Burdock (Arctium lappa L.) is a biennial herb belonging to Asteraceae and is cultivated in several countries. The present study investigated the phytotoxic activity of burdock and its active substances. Extracts of both burdock leaves and roots inhibited the shoot and root growth of cress and barnyard grass, where the level of inhibition increased with increasing extract concentration. The leaf extracts had 2.0-2.5 times higher activity than the root extracts. Bioassay-guided separations of the leaf extracts led to isolation of a phytotoxic substance, onopordopicrin. Onopordopicrin significantly inhibited the shoot and root growth of cress and barnyard grass. The concentrations of the substance required for 50% growth inhibition were 0.27 and 0.26 mM for cress shoots and roots, respectively, and 1.86 and 0.35 mM for barnyard grass shoots and roots, respectively. The present results suggest that burdock leaves have high phytotoxic activity and onopordopicrin may play a major role in the activity. Burdock leaves may be a good resource for weed management.

Allelopathic Potency and an Active Substance from Anredera cordifolia (Tenore) Steenis

Anredera cordifolia (Tenore) Steenis is widely planted as an ornamental and medicinal plant in Indonesia. On the other hand, in some other countries this plant is classified as a noxious weed. As a harmful weed, A. cordifolia is reported to have the ability to smother all native vegetation, collapse canopies of tall trees, cultivate as a ground cover and disrupt native seedling development. There is no available information about the involvement of any allelochemicals from A. cordifolia related to these issues. The present study evaluated the allelopathic effect by isolating and identifying the allelopathic substance from A. cordifolia leaf extract. The allelopathic potency of A. cordifolia was determined by a series of bioassays of shoot and root growth on some selected test plants. Separation and purification of the active substances was achieved through several chromatography processes. Finally, the substances with allelopathic activity were identified through high-resolution electrospray ionization mass spectrometry (HRESIMS) analysis and determined by the specific rotation of compound, proton and carbon NMR spectroscopies. The results show that A. cordifolia possesses allelopathic properties which affect other plant species. The isolated compound from the plant material, 3-hydroxy-alpha-ionone, may contribute to the allelopathic effects of A. cordifolia.