Acetylenes and dichloroanisoles from Psathyrella scobinacea

The alkynyl-containing compounds from mushrooms and their biological activities

Mushrooms have been utilized by humans for thousands of years due to their medicinal and nutritional properties. They are a crucial natural source of bioactive secondary metabolites, and recent advancements have led to the isolation of several alkynyl-containing compounds with potential medicinal uses. Despite their relatively low abundance, naturally occurring alkynyl compounds have attracted considerable attention due to their high reactivity. Bioactivity studies have shown that alkynyl compounds exhibit significant biological and pharmacological activities, including antitumor, antibacterial, antifungal, insecticidal, phototoxic, HIV-inhibitory, and immunosuppressive properties. This review systematically compiles 213 alkynyl-containing bioactive compounds isolated from mushrooms since 1947 and summarizes their diverse biological activities, focusing mainly on cytotoxicity and anticancer effects. This review serves as a detailed and comprehensive reference for the chemical structures and bioactivity of alkynyl-containing secondary metabolites from mushrooms. Moreover, it provides theoretical support for the development of chemical constituents containing alkynyl compounds in mushrooms based on academic research and theory.

Unique functional responses of fungal communities to various environments in the mangroves of the Maowei Sea in Guangxi, China

Fungi are important compartments of microbial communities of mangroves. Their diversity might be influenced by their habitat environment. This study analyzed the distribution and function of fungal communities in the sediments and plant samples from mangrove ecosystem of the Maowei Sea area in Guangxi, China. The results showed that phytopathogenic fungi Cladosporium (17.00%) was mainly observed in the sediments from the protected zone, while endophytic fungi Alternaria (9.22%) and Acremonium (6.09%) were only observed in the sediments from wharf. The fungi in the sediments from village and park were mainly consisted of high-activity endophytes and fungi related to lignin-degrading, respectively. Acaulospora and Aspergillus with higher relative abundance discovered in plant tissues could help plant growth. Cirrenalia (37.66%) and Lignincola (26.73%) with high-activity for lignin-degrading were discovered in decayed leaves. The distribution and function of fungi were highly dependent on the environment settings, thus the fungi can be used as indicators for monitoring the environmental change of mangrove ecosystems.

Antimicrobial activity of the volatile compound 3,5-dichloro-4-methoxybenzaldehyde, produced by the mushroom Porostereum spadiceum, against plant-pathogenic bacteria and fungi

AIMS

In this study, volatile compounds released from mycelia of some aromatic mushrooms were investigated for their inhibitory activity against plant-pathogenic bacteria and fungi.

METHODS AND RESULTS

A screening revealed that volatile compounds from mycelia of Porostereum spadiceum remarkably inhibited the colony formation of plant-pathogenic bacteria, including Clavibacter michiganensis subsp. michiganensis and Ralstonia solanacearum while also inhibiting the conidial germination of plant-pathogenic fungi including Alternaria brassicicola and Colletotrichum orbiculare. The volatile compounds were isolated from the culture filtrate of P. spadiceum, and 3,4-dichloro-4-methoxybenzaldehyde (DCMB) was identified as a major compound. DCMB significantly inhibited bacterial colonization at 10 μg ml^-1 and fungal conidial germination at 0·1-1 μg ml^-1 as a vapour.

CONCLUSIONS

This is the first report on the production of the volatile compound DCMB by P. spadiceum and on the antimicrobial activity of DCMB against plant-pathogenic bacteria and fungi at low concentrations. It may be possible to use the compound as an agent for protecting crops from bacterial and fungal diseases during cultivation and storage.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study provides an understanding of antimicrobial activity of the mushroom volatile compound that may be useful as a novel biological control agent for protecting various plant diseases.

Synthesis of (12R,13S)-pyriculariol and (12R,13S)-dihydropyriculariol revealed that the rice blast fungus, Pyricularia oryzae, produces these phytotoxins as racemates

Synthesis of assumed natural (12R,13S)-enantiomers of pyriculariol (1) and dihydropyriculariol (2), phytotoxins isolated from rice blast disease fungus, Pyricularia oryzae, was achieved using Wittig reaction or microwave-assisted Stille coupling reaction as the key step. The synthesis revealed that the natural 1 and 2 are racemates. Foliar application test on a rice leaf indicated that both the salicylaldehyde core and side chain were necessary for phytotoxic activity. The fungus is found to produce optically active phytotoxins when incubated with rotary shaker, but racemic ones when cultured using an aerated jar fermenter.

A Viscidane Diterpene and Polyacetylenes from Cultures of Hypsizygus marmoreus

Investigation on the cultures of Hypsizygus marmoreus resulted in the isolation of a new viscidane diterpene, 8-oxoviscida-3,11(18)-diene-13,14,15,19-tetraol (1) and two new polyacetylenes, (E)-10-(1,1-dimethyl-2-propenyloxy)-2-decene-4,6,8-triyn-1-ol (2) and 10-(1,1-dimethyl-2-propenyloxy)deca-4,6,8-triyn-1-ol (3), together with two known polyacetylenes, (E)-2-decen-4,6,8-triyn-1-ol (4) and 4,6,8-decatriyn-1-ol (5). Their structures were elucidated on the basis of extensive spectroscopic studies. Compound 1 is the first finding of viscidane diterpene in mushrooms. Compounds 1, 3 and 5 were tested for cytotoxicity against human tumor cell lines HL-60, SMMC-7721, A-549, MCF-7 and SW-480. None of the compounds showed cytotoxic activity (IC50 > 40 µM).

Food protective effect of acaricidal components isolated from anise seeds against the stored food mite, Tyrophagus putrescentiae (Schrank)

The acaricidal activity of anise seed-isolated anisaldehyde and commercially available components of anise seed was examined against Tyrophagus putrescentiae adults and compared with those of synthetic acaricides, benzyl benzoate, dibutyl phthalate, and N,N-diethyl-m-toluamide (DEET). On the basis of LD50 (50% lethal dose) values, the compound most toxic to T. putrescentiae adults was anisaldehyde (LD50, 0.96 microg/cm2), followed by benzyl benzoate (LD50, 11.3 microg/cm2), anethole (LD50, 12.3 microg/cm2), dibutyl phthalate (LD50, 13.3 microg/cm2), DEET (LD50, 13.5 microg/cm2), estragole (LD50, 17.4 microg/cm2), and myrcene (LD50, 56.2 microg/cm2). Anisaldehyde was about 11.8 and 14 times more toxic than benzyl benzoate and DEET against T. putrescentiae adults, respectively. The results suggested that anisaldehyde, anethole, estragole, and myrcene derived from anise seeds are useful as a lead compound to development new agents for selective control of the stored food mite.

Formation and emission of chloroanisoles as indoor pollutants

GOAL, SCOPE AND BACKGROUND

Complaints by residents of frame-houses about musty odour in the houses has become an increasing problem within the last years. An additional problem is that the odour is transferred to clothes and skin. The persons themselves do not recognize the smell after a while because of adaptation. Serious social problems are the result. For a long time, the smell was explained to be from mould due to construction-based humidity problems. However, in an increasing number of houses, no indications were found for elevated levels of mould growth.

METHODS

Air and material samples were taken from 5 houses, which show typical musty odours, and analysed with respect to chlorophenols and chloroanisoles. Additionally, some samples were analysed for lindane and its metabolites, because lindane was commonly used together with pentachlorophenol (PCP) for wood protection.

RESULTS AND DISCUSSION

Meticulous analysis resulted in the identification of chloroanisoles, mainly 2,3,4,6-tetrachloroanisole. These substances are known from corky wines and from contamination of food from pentachlorophenol (PCP) treated pallets and result from microbiological metabolic processes. Pentachlorophenol was commonly used to protect wood from fungi in Germany mainly in the later 60s and 70s. Details of these processes, as well as effective methods to identify chloroanisoles in the problem houses, are described.

CONCLUSIONS

Chloroanisoles formed by metabolism of PCP have been well known to contaminate food or wine. Here, they were identified and are probably responsible for the musty odours in the frame houses. Since it is quite clear that these substances were not components of building materials used in the houses, an explanation for chloroanisole formation is proposed. Localized dampness probably favours microbial growth associated with metabolic conversion of chlorophenols to the corresponding chloroanisoles, primarily 2,3,4,6-tetrachloroanisol, which spread throughout the buildings, resulting in the observed odours.

RECOMMENDATIONS AND OUTLOOK

The group of chloroanisoles has been recognized as important indoor pollutants as they possess musty odours at extremely low concentrations, e.g. for 2,4,6-trichloroanisole in a range of 5-10 ppt in air (Staples 2000). On the basis of currently available toxicological data, exposure of the occupants to the concentrations of chloroanisoles measured is not associated with a health risk. No correlation could be observed between concentrations of chloroanisoles and PCP in house dust and indoor air. However, chloroanisoles are good indicators for possible PCP-treatment of wood in frame houses and their detection should initiate investigations on PCP contamination. Research is continuing to identify the microorganisms involved and to devise a remediation procedure for affected houses.