2.1 Linear alkynyl with C ≤ 10

Linear alkynyl with C ≤ 10 refers to compounds containing ten carbon atoms or fewer in the long chain that includes the alkynyl group. Various modifications, such as hydroxylation and carboxylation, occur at the end of linear alkynyl. A total of 56 types of these compounds have been identified.

2.1.1 Linear alkynyl with C ≤ 9

Linear alkynyl with C ≤ 9 contain nine or fewer carbon atoms in the long chain, including the alkynyl group. The termini of linear alkynyl undergo various modifications such as hydroxylation, carboxylation. A total of 32 compounds were identified.

1-hydroxy-2-nonyn-4-one (1) was isolated from Ischnoderma benzoinum, which shows significant inhibitory activity against yeasts and filamentous fungi at concentrations ranging from 1 to 5 μg/mL [9]. Moreover, at the same concentrations, 1 strongly inhibits nucleic acid, and protein syntheses in cells of the ascitic form of Ehrlich carcinoma [9]. Acetylenic diol (2) was isolated from of cultures Clitocybe catinus [10]. Compound 3 was isolated from Fomes annosus [11]. Hepta-4,6-diyn-3-ol (4), 7-chloro-hepta-4,6-diyn-3-ol (5) were isolated from Gymnopilus spectabilis [12], compound 5 is also one of the metabolites of G. hybridus [13]. Compounds 4 and 5 exhibit antibacterial activity by agar diffusion test [12]. When tested at a concentration of 100 μL/mL per disc, compound 4 exhibits inhibition against the following bacteria including Bacillus brevis [12]. Scobinynediol-II (6), scobinynediol-II (7), scobinynediol-I (8) and octa-2,4,6-triynoic acid (9) were isolated from the culture medium Psathyrella scobinacea [14]. Triynol (10), triyne acid (11), and triyne alcohol (12) were isolated from Psilocybe merdaria, Kuehneromyces mutabilis, Russula vesca and Ramaria flava [13]. Polyacetylenic acid (13) was isolated from Camarophyllus virgineus [15]. Compounds 14 and 15 were isolated from Poria sinuosa [16], and Compound 14 was isolated from Coprinus species [17]. Compound 16 was isolated from the culture of Poria cocos, which exhibited significant nematicidal activity against Meloidogyne arenaria and Panagrellus redivivus [18]. Compound 17 was isolated from P. sinuosa [16]. Lentinamycin (18) was isolated from Lentinula edodes, demonstrating antibacterial activity against common bacterias and pathogenic bacteria in an antibacterial activity test using the paper disk method (31.3 nM/disk) [19,20,21,22]. Compound 18 also showed antimicrobial activity against a variety of filamentous fungi such as Aspergillus and yeasts, as well as anti-gram-positive bacterial activity with the minimum inhibitory concentration (MIC) value of 0.085–0.42 μM [19, 23]. Pyranone derivative B (19) was isolated from Junghuhnia nitida. It displayed cytotoxicity against five human cancer cell lines, including human myeloid leukemia HL-60, hepatocellular carcinoma SMMC-7721, lung cancer A-549, breast cancer MCF-7, and colon cancer SW480, with IC50 > 40 μM [24]. Compounds 20 and 21 were isolated from Fistulina pallida [25]. Compound 22 was isolated from Serpula lacrymans [13]. (Z)-non-7-en-5-yn-1,2,4-triol (23), (Z)-non-7-en-5-yn-1,4-diol (24), (Z)-1,2-dihydroxynon-7-en-5-yn-4-one (25), (Z)-1-hydroxynon-7-en-5-yn-4-one (26) were isolated from Tricholoma pardinum [26]. The allenediyne (-)-marasin (27) was extracted as an active antibiotic component against S. aureus from a culture of Marasmius ramealis in 1959, and was the first naturally occurring olefin to be isolated [27]. Compound 27 was also found to exhibit antibacterial and antimycobacterial activities [28]. Scorodonin (28) is a bioactive metabolite isolated from Marasmius scorodonius, which exhibits inhibitory effects on the growth of bacteria, yeast, and filamentous fungi [29]. Compound 28 also showed significant inhibition of nucleic acid [29]. Compounds (29)–(32) were isolated from L. edodes [21]. Among them, compounds 29 and 32 were specifically obtained from the liquid culture filtrate and exhibited antifungal activity [21, 22]. The structures of these compounds are shown in Fig. 1.

Fig. 1

Chemical structures of linear alkynyl with C ≤ 9

2.1.2 Linear alkynyl with C = 10

A total of 24 long-chain compounds consisting of 10 carbon atoms containing alkynyl groups were identified (Fig. 2). Two compounds, (2E)-decane-4,6,8-trienoic acid (33) and (2E)-decene-4,6,8-triyn-1-ol (34), were isolated from the fruit body of Lyophyllum decastes, a wild lotus leaf found in the Qilian Mountains [30]. These two compounds exhibit significant anti-oxidant activity against 2,2′-azobis (2-amidinopropane) dihydrochloride (ABAP) with EC50 values of 46.33 ± 3.48 μM/L, 65.6 ± 2.98 μM/L, respectively [30]. Notably, 34 was also identified from the metabolites of Hypsizygus marmoreus [31], P. sinuosa [16], Lentinus lepideus, Leucopaxillus giganteus, Lyophyllurn dacastes and Peniophora resinosa [32]. 4,6,8-decatriyn-1-ol (35) was isolated from H. marmoreus [31] and P. scobinacea [14]. Compound 36 was isolated from H. marmoreus [33]. (3S,8S)-(-)-4,6-decadiyne-l,3,8-triol (37) was isolated from G. spectabilis [34]. Compounds 38 and 39 were isolated from F. pallida [25]. Compounds 40–42 were found in C. virgineus [15]. Polyacetylenic compounds 43–46 were isolated from P. sinuosa [16]. Compound 47 was isolated from L. lepideus, L. giganteus, L. dacastes, and P. resinosa [32]. Masutakic acid A (48) was isolated from the fruiting bodies of Laetiporus sulphureus [35]. Compounds 49–51 were isolated from S. lacrymans [13]. Acetylenic diols, 52 and 53, were isolated from the cultures of C. catinus, which exhibited anti-B. subtilis and anti-B. cereus activities at a concentration of 50 μg per disk [10]. Triynol (54) was isolated from the culture medium P. scobinacea [14]. Chondrosterin G (55) and chondrosterin H (56) were isolated from Chondrostereum species [36].

Fig. 2

Chemical structures of linear alkynyl with C = 10

2.2 Linear alkynyl containing amino or amide acids at the end

These compounds are long-chain alkynyl structures with amino, carboxyl, and amide bonding modifications at the linear alkynyl ends. A total of 24 such compounds have been reported (Fig. 3A).

Fig. 3

Chemical structures of linear alkynyl containing amino or amino acids at the end (A), and O-isopentenyl at the end (B)

Diatretyne amide (57) and diatretyne nitrile (58) were isolated from cultures of Clitocybe diatreta and showed broad-spectrum antimicrobial activity [37]. Among them, 58 showed the most prominent inhibitory activity against S. aureus with a MIC value of 30 ng/mL [37]. In addition, mushrooms capable of producing 58 is C. virgineus [15]. (2S)-2-amino-4-pentynoic acid (59), (2S)-2-aminohept-4-en-6-ynoic acid (60) were isolated from the fruiting body of Amanita pseudoporphyria [38]. (2R)-2-amino-6-hydroxy-4-hexynoic acid (61) was isolated from Amanita miculifera [39]. Propargylglycine (2-amino-4-pentynoic acid, 62), an acetylated amino acid, was identified in the poisonous Amanita abrupta [40], and it is hypothesized that 62 may inhibit fatty acid oxidation [40]. A toxic amino acid, (2S,3R)-2-amino-3-hydroxypent-4-ynoic acid (63) was isolated from Sclerotium rolfsii, and was lethal to New Hampshire chickens with LD50 of 150 mg/kg [41]. Six amino acid derivatives, (2S)-2-amino-4-hexynoic acid (64), (2S)-2-amino-3-hydroxy-4-hexynoic acid (65), γ-L-Glutamyl-(2S)-2-amino-4-hexynoic acid (66), γ-Glutamyl-(2S,3S)-2-amino-3-hydroxy-4-hexynoic acid (67), γ-glutamyl-L-2-aminohex-4-ynoic acid (68) and γ-L-glutamyl-L-erythro-2-amino-3-hydroxyhex-4-ynoic acid (69) were isolated from the fruiting body of Tricholomopsis rutilans. These amino acid derivatives have antiviral, anticholesterol, and anticancer activities [42,43,44]. (2S)-2-amino-5-hexynoic acid (70) was isolated from the fruiting body of Cortinarius claricolor var. tenuipes Hongo, which was characterized as a strong growth inhibitor against B. subtilis B-50 [45]. Agrocybin (71) was isolated from cultures of the fungi Agrocybe perfecta (Rick) Singer [46], Agrocybe dura [46], and Cantharellus formosus [47]. Intensive bioactivity investigations showed that 71 not only possessed trypanothione reductase inhibitory activity (IC50 2 μM) but was also toxic to white mice (LD50 6 mg/kg) [46]. It was also found to have significant activity against the human cancer cell lines UACC-62, MCF-7, and TK-10. In addition, 71 has phytotoxic, antibacterial, and antifungal activities [46, 48]. Agrocybynes A–E (72–76) were isolated from Agrocybe praecox, 72–75, and were found to have significant growth inhibitory activity against lettuce [49]. 10-hydroxyundeca-2,4,6,8-tetraynamide (77) was isolated from Mycena viridimarginata, which demonstrates both antibacterial and antifungal activities [50]. Two unusual amino acids, 2R-amino-4S-hydroxy-5-hexynoic acid (78), and 2R-amino-5-hexynoic acid (79) were isolated from Trogia venenata, which showed low-dose toxic to mice [51]. Compound 80 was isolated and characterized from P. sinuosa [16]. The structures, names, biological activities, and sources of these compounds are shown in Fig. 3 and Table 1.

2.3 Linear alkynyl containing O-isopentenyl at the end

This group contains compounds O-isopentenyl modifications, and has a backbone of at least two alkynyl groups. Isoprenyl ether (81) was isolated from Fayodia bisphaerigera [52]. (E)-10-(1,1-dimethyl-2-propenyloxy)-2-decene-4,6,8-triyn-1-ol (82) and 10-(1,1-dimethyl-2-propenyloxy)deca-4,6,8-triyn-1-ol (83) were isolated from H. marmoreus [31]. Their structures are displayed in Fig. 3B. No biological activity has been reported for any of these three compounds.

2.4 Linear alkynyl with C > 10

These compounds are characterized by the presence of at least one alkynyl group and a linear chain of more than ten carbon atoms. Hydroxylation, carboxylation, and other modifications are present at their termini, and a total of 49 compounds have been identified.

2.4.1 Linear alkynyl with C11–C17

These compounds consist of long chains of alkynyl groups of eleven to seventeen carbon atoms, containing up to four alkynyl groups. A total of 22 such compounds have been identified (Fig. 4).

Fig. 4

Chemical structures of linear alkynyl with C11–C17

Nemotinic acid (84) was isolated from Basidiomycete B-841, which exhibited antibacterial and antimycobacterial activities [28, 53,54,55,56,57]. Compounds 85–86 were separated from L. lepideus, L. giganteus, L. dacastes, and P. resinosa [32]. 87 was isolated from Cortinellus berkeleyanus [20]. Compound 88 was isolated and characterized from P. sinuosa [16]. Tetrayne tetraol (89) was isolated from the culture of Fistulina hepatica [25]. Five polyacetylenic compounds (90–94), namely Feldin, 4-dodecene-6,8-diyne-1,3,10-triol, falcarinol, falcarindiol, and oenanthetol, were also the metabolites of F. hepatica [58]. Triynene diol (95) was isolated from F. pallida [25]. Phomallenic acids A–B (96–97) were extracted from Phoma species [59], which showed type II fatty acid synthesis inhibitory activity [59]. Mycomycin (98) was isolated from C. formosus [47]. 14-oxo-9,15-octadecadien-12-ynoic acid (99) and 14-oxo-9,15-octadecadien-12-ynoic acid methyl ester (100) were isolated from Cantharellus cibarius [60]. Dehydromatrine ethyl ester (101) was isolated from the fruit body of L. decastes [30]. It exhibited significant anti-oxidant activity against 2,2′-azobis (2-amidinopropane) dihydrochloride (ABAP) with EC50 values of 43.4 ± 2.05 μM/L [30]. Dehydromatricaria acid (102) and compound (103) were isolated from the culture medium P. scobinacea [14]. Compounds 104 and 105 were isolated from Polyporus species [61].

2.4.2 Linear alkynyl with C = 18

These long-chain compounds containing alkynyl groups consist of eighteen carbon atoms, and sixteen compounds have been identified (Fig. 5A).

Fig. 5

Chemical structures of linear alkynyl with C18 (A), and C > 18 (B)

(8E,10R,14Z)-10-hydroxy-8,14-octadecadien-12-ynoic acid (106) was isolated from Craterellus aureus [62]. Craterellyne E (107), compound 108, craterellyne F (109), craterellyne J (110), craterellyne M (111), and craterellyne P (112) were isolated from Craterellus lutescens [63, 64]. Phomallenic acid C (113) was extracted from Phoma species, which exhibited inhibitory against the wild-type S. aureus with the MIC of 3.9 μg/mL[59]. (10