Biotransformation of artemisinic acid by the fungus Trichothecium roseum and anti-candidal activity of its metabolites

The microbial transformation of artemisinic acid (1) using cell culture of endophytic fungus Trichothecium roseum was investigated. Previously, we have reported two major metabolites, 3β-hydroxyartemisinic acid (2) and 3β,15-dihydroxyartemisinic acid (3) from the biotransformation of artemisinic acid by the fungus T. roseum CIMAPN1. Here in the present paper, we obtained a new minor compound 4 (5.2% in yield) along with compounds 2 and 3 through scale-up of biotransformation process of artemisinic acid using the same fungus. The structure of compound 4 was established as 3-oxoartemisinic acid on the basis of its IR, ESI-MS, HRMS, 1?D (¹H and ¹³C, DEPT), and 2?D (COSY, HSQC, HMBC) NMR spectral data analysis. The possible reaction mechanism of the formation of 3-oxoartemisinic acid from artemisinic acid was proposed. Furthermore, all the three metabolites along with the artemisinic acid were evaluated for their antifungal activity against the three fungal strains Candida albicans (ATCC 14053), Candida albicans clinical isolates and Candida kefyr (ATCC 204093). 3-Oxoartemisinic acid was the most active (4 to 16 times more potent than artemisinic acid) with MIC ranges from 125 to 500?µg/mL among all tested compounds. This study suggested that the artemisinic acid molecule has a great potential to be exploited for further biotransformation by the different fungi and can produce chemically diverse molecules with better biological activity.     

Biotransformation of isoimperatorin by Cunninghamella blakesleana AS 3.970

The biotransformation of isoimperatorin (1) by Cunninghamella blakesleana AS 3.970 yielded 6 novel products, 14-hydroxyl-isoimperatorin (2), 11-carbonyl-14-hydroxyl isoimperatorin (3), 11-carbonyl-14-hydroxyl-12,13-dihydrogen-iso-imperatorin (4), 14-hydroxyl-12,13-dihydrogenisoimperatorin (5), isoimperatorin-14-O-β-d-mannoside (6) and isoimperatorin-14-O-β-d-glucoside (7), respectively. The chemical structures of these metabolites were elucidated based on extensive spectral data including 2D NMR and HRMS. The hydroxylation, hydrogenation, carbonylation and glycosylation reactions of 1 by C. blakesleana AS 3.970 were observed in the present study. In addition, anti-osteoporosis activities of substrate and all transformed products were evaluated by using MC3T3-E1 cells. Our results suggested that hydroxylation or glycosylation of C-14 would enhance anti-osteoporosis activity significantly.     

Biotransformation of eugenol by suspension cultures of transgenic crown galls of <Emphasis Type="Italic">Panax quinquefolium</Emphasis> and suspension cultures of <Emphasis Type="Italic">Nicotiana tabacum</Emphasis>

The biocatalytic ability of transgenic crown galls of Panax quinquefolium was evaluated by using eugenol (1) as a substrate and suspension cultures of Nicotiana tabacum as control system. Three biotransformed products, namely: 2-methoxy-4-(2-propenyl)phenyl-O-β-d-glucopyranoside (2, 67.11%), 2-methoxy-4-(2-propenyl)phenyl-O-β-d-glucopyranosyl (6′ → 1″)-β-d-xylopyranoside (3, 2.85%) and methyl eugenol (4, 14.30%) were obtained after 5 days of administration of eugenol to the suspension cultures of transgenic crown galls of P. quinquefolium. In contrast, only one product, compound 2 (15.41%), was obtained in suspension cultures of N. tabacum after 5 days of incubation. The results indicated that the glycosylation ability of transgenic crown galls of P. quinquefolium was much higher than that of the cultured cells of N. tabacum.     

Microbial transformation of glycyrrhetinic acid derivatives by Bacillus subtilis ATCC 6633 and Bacillus megaterium CGMCC 1.1741

Glycyrrhetinic acid (GA), the major bioactive pentacyclic triterpene aglycone of licorice root, was known to play a vital role in anti-ulcer, anti-depressant, anti-inflammatory, and anti-allergic. In this study, we semi-synthesized five GA derivatives by a series of chemical reactions. They were selected as substrates for the biotransformation and yielded thirteen metabolites by Bacillus subtilis ATCC 6633 and Bacillus megaterium CGMCC 1.1741. Their structures were identified on the basis of extensive spectroscopic methods and nine of them were found for the first time. Two main types of reactions, regio- and stereo-selective hydroxylation and glycosylation, especially in the unactivated C-H bonds including C-11, C-19 and C-27, were observed in the biotransformation process, which greatly expand the chemical diversities of GA derivatives. All compounds were tested for their inhibitory effects on nitric oxide (NO) generation in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells. Among them, olean-12-ene-3β,7β,15α,19α,30-pentol (16) and olean-12-ene-3β,7β,15α,27,30-pentol (17) showed significant inhibitory effect with IC₅₀ values of 0.64 and 0.07 μM, respectively.     

Cytotoxic biotransformed products from andrographolide by Rhizopus stolonifer ATCC 12939

Biotransformation of andrographolide (1) by Rhizopus stolonifer ATCC 12939 was investigated. Ten bioconversion products were isolated and identified. Their structures were elucidated by high resolution mass spectroscopy (HR-MS), extensive NMR techniques, including ¹H NMR, ¹³C NMR, DEPT, ¹H–¹H correlation spectroscopy (COSY), two dimensional nuclear Overhauser effect correlation spectroscopy (NOESY), heteronuclear multiple quantum coherence (HMQC) and heteronuclear multiple bond coherence (HMBC). Their structures were identified to be 12(R),13(R)-12-hydroxyandrographolide (2), 12(S),13(S)-12-hydroxyandrographolide (3), isoandrographolide (4), 3-dehydro-isoandrographolide (5), 14-deoxy-11,12-didehydroandrographolide (6), 3-oxo-14-deoxy-11,12-didehydroandrographolide (7), 3-dehydroandrographolide (8), 14-deoxyandrographolide (9), 3-dehydro-14-deoxyandrographolide (10) and 3-dehydro-14-deoxyandrographolide-19-oic acid (11). Among them, compounds 5 and 11 are novel compounds. The biosynthetic pathways of andrographolide by R. stolonifer were proposed. Most of the products showed potential antiproliferative activities against human breast cancer (MCF-7), human colon cancer (HCT-116) and human leukemia (HL-60) cell lines, and their structure–activity relationships (SAR) were discussed in detail.     

Biotransformation of Methylphenylacetonitriles by Brazilian Marine Fungal Strain Aspergillus sydowii CBMAI 934: Eco-friendly Reactions

This study reports the biotransformation of methylphenylacetonitriles by Brazilian marine filamentous fungus Aspergillus sydowii CBMAI 934 under eco-friendly reaction conditions. The phenylacetonitrile 1, 2-methylphenylacetonitrile 2, 3-methylphenylacetonitrile 3, and 4-methylphenylacetonitrile 4 were quantitatively biotransformed into 2-hydroxyphenylacetic 1a, 2-methylphenylacetic acid 2a, 3-methylphenylacetic acid 3a, and 4-methylphenylacetic acid 4a by enzymatic processes using whole cell as biocatalyst. The marine fungus A. sydowii CBMAI 934 is thus a promising biocatalyst for the preparation of important carboxylic acids under mild conditions (pH 7.5 and 32 °C) from nitrile compounds.     

Microbial transformation of acetyl-11-keto-β-boswellic acid and their inhibitory activity on LPS-induced NO production

The capabilities of 20 strains of fungi to transform acetyl-11-keto-β-boswellic (AKBA) were screened. And biotransformation of AKBA by Cunninghamella blakesleana AS 3.970 afforded five metabolites (1–5), while two metabolites (6, 7) were isolated from biotransformation of Cunninghamella elegans AS 3.1207. The chemical structures of these metabolites were identified by spectral methods including 2D NMR and their structures were elucidated as 7β-hydroxy-3-acety-11-keto-β-boswellic acid (1), 21β-dihydroxy-3-acety-11-keto-β-boswellic acid (2), 7β,22α-dihydroxy-3-acety-11-keto-β-boswellic acid (3), 7β,16α-dihydroxy-3-acety-11-keto-β-boswellic acid (4), 7β,15α-dihydroxy-3-acety-11-keto-β-boswellic acid (5); 7β,15α,21β-trihydroxy-3-acety-11-keto-β-boswellic acid (6) and 15α,21β-dihydroxy-3-acety-11-keto-β-boswellic acid (7). All these products are previously unknown. Their primary structure–activity relationships (SAR) of inhibition activity on LPS-induced NO production in RAW 264.7 macrophage cells were evaluated.     

Biotransformation of columbianadin by rat hepatic microsomes and inhibition of biotransformation products on NO production in RAW 264.7 cells in vitro

Columbianadin (CBN, 1), 1-[(8S)-8,9-dihydro-2-oxo-2H-furo[2,3-h]-1-benzopyran-8-yl]-1-methylethyl-[(2Z)-2-methyl-2-butenoic acid]ester is a coumarin-type compound and one of the main bioactive constituents of the underground part of Angelica pubescens Maxim. f. biserrata Shan et Yuan. Although numerous investigations have been undertaken to study the biological activities of CBN, such as analgesic, anti-inflammatory, calcium-channel blocking, and platelet aggregation inhibiting functions, little attention has been paid to its metabolism and/or biotransformation. Biotransformation of CBN by rat liver microsomes in vitro was studied, and thirteen biotransformation products including eight hitherto unknown compounds [columbianadiratimetins A-H (3–10)] and five known compounds [columbianadin oxide (2), (+)-2,3-dihydro-4-hydroxy-2-(1-hydroxy-1-methylethyl)-5-benzofurancarboxaldehyde (11), oroselol (12), columbianetin (13), and vaginol (14)] were produced by liver microsomes from rats pre-treated with sodium phenobarbital. The structures of these compounds were elucidated on the basis of extensive spectroscopic analyses which included IR, UV, EIMS, HRESIMS, 1D NMR and 2D NMR, respectively. The inhibition of CBN and its main biotransformation products on nitric oxide production induced by lipopolysaccharide was assayed in RAW 264.7 cells at concentrations ranging from 10 to 200 μM to evaluate the biological significance of biotransformation.     

Phytochemical and chemotaxonomic study of Pulsatilla cernua (Thunb.) Bercht. ex J. Presl

Twenty-two compounds were isolated from the 70% EtOH–H₂O extract of Pulsatilla cernua (Thunb.) Bercht. ex J. Presl roots, and their structures were determined based on ¹H NMR, ¹³C NMR and MS spectroscopic data, including (+)-pinoresinol (1), matairesinol (2), 4-ethoxycinnamic acid (3), p-hydroxy ethyl cinnamate (4), 3-(4′-methoxyphenyl)-2(E)-propenoic acid (5), methyl 4-hydroxycinnamate (6), radicol (7), cryptomeridiol (8), fraxinellone (9), diolmycin B2 (10), hederagonic acid (11), hederagenin (12), oleanolic acid (13), 3-O-α-L-arabinopyranosyl-oleanolic acid (14), hederagenin 3-O-α-L-arabinopyranoside (15), 3-O-[α-L-rhamnopyranosyl-(1→2)-α-L-arabinopyranosyl] oleanolic acid (16), hederasaponin B (17), kizutasaponin K₁₂ (18), patrinia saponin H3 (19), hederacholichiside F (20), cernuoside A (21) and cernuoside B (22). Eight compounds (3–10) were isolated and identified from the genus Pulsatilla for the first time.     

Ehrenasterol and biemnic acid; new bioactive compounds from the Red Sea sponge Biemna ehrenbergi

In continuation of our efforts to identify bioactive compounds from the Red Sea marine sponges, we have recently investigated the organic extract of the sponge Biemna ehrenbergi. This study resulted in the isolation of eight compounds including a new sterol, ehrenasterol (1), a new C₂₄-acetylenic acid, biemnic acid (2), together with six known compounds including a hopanoid, three steroids and two nucleosides. The isolated compounds were identified as (22E)-ergosta-22-ene-8,14-epoxy-3,7-dione (1), (E)-tetracos-8-en-5-ynoic acid (2), (22E)-ergosta-5,8,22-trien-7-one-3β-ol (3), 32,35-anhydrobacteriohopanetetrol (4), (24R)-ergosta-6,22-diene-5,8-epidioxy-3-ol (5), melithasterol B (6), thymidine (7) and 2′-deoxyuridine (8). The structures of the isolated compounds were assigned by different spectral data including 1D and 2D NMR (COSY, HSQC, and HMBC) and high-resolution mass spectrometry. Compound 1 displayed inhibition zone of 20 mm at 100 μg/disc against Escherichia coli in the disc diffusion assay. Similarly, compounds 2 and 4 displayed inhibition zones of 20 and 18 mm respectively against Candida albicans at the same concentration. Compounds 1–3 displayed weak cytotoxic activity against human colon adenocarcinoma (HCT-116) cancer cell line.     

Biotransformation of ent-kaur-16-ene and ent-trachylobane 7β-acetoxy derivatives by the fungus Gibberella fujikuroi (Fusarium fujikuroi)

Candol A (7β-hydroxy-ent-kaur-16-ene) (6) is efficiently transformed by Gibberella fujikuroi into the gibberellin plant hormones. In this work, the biotransformation of its acetate by this fungus has led to the formation of 7β-acetoxy-ent-kaur-16-en-19-oic acid (3), whose corresponding alcohol is a short-lived intermediate in the biosynthesis of gibberellins and seco-ring ent-kaurenoids in this fungus. Further biotransformation of this compound led to the hydroxylation of the 3β-positions to give 7β-acetoxy-3β-hydroxy-ent-kaur-16-en-19-oic acid (14), followed by a 2β- or 18-hydroxylation of this metabolite. The incubation of epicandicandiol 7β-monoacetate (7β-acetoxy-18-hydroxy-ent-kaur-16-ene) (10) produces also the 19-hydroxylation to form the 18,19 diol (20), which is oxidized to give the corresponding C-18 or C-19 acids. These results indicated that the presence of a 7β-acetoxy group does not inhibit the fungal oxidation of C-19 in 7β-acetoxy-ent-kaur-16-ene, but avoids the ring B contraction that leads to the gibberellins and the 6β-hydroxylation necessary for the formation of seco-ring B ent-kaurenoids. The biotransformation of 7β-acetoxy-ent-trachylobane (trachinol acetate) (27) only led to the formation of 7β-acetoxy-18-hydroxy-ent-trachylobane (33).     

Nitrous acid deamination of methylated amino-oligosaccharide glycosides

G.l.c.-mass spectrometry has been used to characterize the products of N-deacetylation-nitrous acid deamination of per-O-methylated derivatives (8–11) of methyl 2-acetamido-2-deoxy-3-O-β-D-galactopyranosyl-α-D-glucopyranoside(1), methyl (2) and benzyl (3) 2-acetamido-2-deoxy-4-O-β-D-galactopyranosyl-β-D-glucopyranosides, and methyl 2-acetamido-2-deoxy-6-O-β-D-galactopyranosyl-α-D-glucopyranoside (4). 2,5-Anhydrohexoses have been converted into alditol trideuteriomethyl ethers, alditol acetates, and aldononitriles. The importance of side reactions that lead to the formation of 2-deoxy-2-C-formylpentofuranosides is discussed.     

Alkenylresorcinols and cytotoxic activity of the constituents isolated from Labisia pumila

Phytochemical investigation on the leaves of Labisia pumila (Myrsinaceae), an important medicinal herb in Malaysia, has led to the isolation of 1-O-methyl-6-acetoxy-5-(pentadec-10Z-enyl)resorcinol (1), labisiaquinone A (2) and labisiaquinone B (3). Along with these, 16 known compounds including 1-O-methyl-6-acetoxy-5-pentadecylresorcinol (4), 5-(pentadec-10Z-enyl)resorcinol (5), 5-(pentadecyl)resorcinol (6), (−)-loliolide (7), stigmasterol (8), 4-hydroxyphenylethylamine (9), 3,4,5-trihydroxybenzoic acid (10), 3,4-dihydroxybenzoic acid (11), (+)-catechin (12), (−)-epicatechin (13), kaempferol-3-O-α-rhamnopyranosyl-7-O-β-glycopyranoside (14), kaempferol-4′-O-β-glycopyranoside (15), quercetin-3-O-α-rhamnopyranoside (16), kaempferol-3-O-α-rhamnopyranoside (17), (9Z,12Z)-octadeca-9,12-dienoic acid (18) and stigmasterol-3-O-β-glycopyranoside (19) were also isolated. The structures of these compounds were established on the basis of 1D and 2D NMR spectroscopy techniques (¹H, ¹³C, COSY, HSQC, NOESY and HMBC experiments), mass spectrometry and chemical derivatization. Among the constituents tested 1 and 4 exhibited strongest cytotoxic activity against the PC3, HCT116 and MCF-7 cell lines (IC₅₀ values ⩽10 μM), and they showed selectivity towards the first two-cell lines relative to the last one.     

Chevalierinoside B and C: Two new isoflavonoid glycosides from the stem bark of Antidesma laciniatum Muell. Arg (syn. Antidesma chevalieri Beille)

Chevalierinosides B (1) and C (2), two new isoflavonoid glycosides, characterized as biochanin A 7-O-[β-d-apiofuranosyl-(1→2)-β-d-glucopyranoside] and genistein 7-O-[β-d-apiofuranosyl-(1→2)-β-d-glucopyranoside], together with the known isoflavonoids, chevalierinoside A (3) and genistein 7-O-β-d-glucopyranoside (4), kaempferol 3-O-β-d-glucopyranoside (5) and triterpenes, friedelin (6), betulinic acid (7), 30-oxobetulinic acid (8), 30-hydroxybetulinic acid (9), were isolated from the stem bark of Antidesma laciniatum Muell. Arg. (syn. Antidesma chevalieri Beille). Their structures were established by direct interpretation of their spectral data, mainly HR-TOFESIMS, 1D-NMR (¹H, ¹³C and DEPT) and 2D-NMR (COSY, NOESY, TOCSY, HSQC and HMBC), and by comparison with the literature.     

Synthesis and evaluation of new endomorphin analogues modified at the Pro2 residue

Six new endomorphin analogues, incorporating constrained amino acids in place of native proline have been synthesized. Residues of (S)-azetidine-2-carboxylic acid (Aze), 3,4-dehydro-(S)-proline (Δ³Pro), azetidine-3-carboxylic acid (3Aze) and dehydro-alanine (ΔAla) have been used to prepare [Δ³Pro²]EM-2 (1), [Aze²]EM-1 (2), [Aze²]EM-2 (3), [3Aze²]EM-1 (4), [3Aze²]EM-2 (5) and [ΔAla²]EM-2 (6). Binding assays and functional bioactivities for μ- and δ-receptors are reported. The highest affinity, bioactivity and selectivity are shown by peptides 2 and 3 containing the Aze residue.     

Cytotoxic protobassic acid glycosides from Planchonella obovata leaf

Four triterpenoid glycosides, possessing protobassic acid as common aglycon, together with 16 known compounds were isolated from the leaves of Planchonella obovata. They are 6β-hydroxy-conyzasaponin G (2), 3‴-O-de-β-d-apiofuranosylisoarganin F (3), isoarganin F (4), and 6β-hydroxy-conyzasaponin N (5). The structures of these glycosides were elucidated based on spectroscopic analysis, in particular using 1D TOCSY to confirm the ¹H NMR assignment of each sugar residue. The absolute configuration of each monosaccharide in the glycon part was determined by GC-FID. Compound 5, Mi-saponin A (8), and ursolic acid (10) showed moderate inhibitory activities against HL-60 leukemia cell line with the IC₅₀ values of 16.88, 15.50, and 12.68 μM, respectively.     

New unsaturated fatty acid and other chemical constituents from the roots of Cola rostrata K. Schum. (Malvaceae)

Phytochemical investigation of the roots of Cola rostrata K. Schum. led to the isolation of a new unsaturated fatty acid, named rostratanic acid (1), together with fourteen known compounds, lignoceric acid, friedelan (7), friedelanone (8), bauerenol (3), lupeol (4), herranone (9), acotatarone A (11), betulinic acid (6), betulin (5), nonanedioc acid (2), arjunolic acid (10) stigmasterol, β−sitosterol, and β−sitosterol-3-O-β-D-glucopyranoside. The structure of the new compound as well as those of the known compounds were established by means of spectroscopic methods: NMR analysis (¹H and ¹³C NMR, ¹H–¹H–COSY, HSQC and HMBC) and high-resolution mass spectrometry (HR-ESI-MS), and by comparison with previously reported data. Two of those known compounds were modified chemically to afford three new derivatives. All those compounds were tested for their cytotoxic activity against the human cervix carcinoma KB-3-1 cells and their antibacterial activity against Escherichia coli, Salmonella enterica, Pseudomonas aeruginosa and Staphylococcus aureus. Although the crude extract gave weak antibacterial activity, none of the isolated compounds showed antibacterial activity, and, only the prenylated derivative showed weak cytotoxicity. In addition, the chemotaxonomic significance of the species Cola rostrata is discussed.     

Phenolic acid glycosides from Parmentiera cereifera Seem. (Candle tree)

Two new phenolic acid glycosides, parmentins A (1) and B (2) were isolated from the methanolic extract of the leaves and stems of candle tree (Parmentiera cereifera Seem). These compounds were accompanied by a mixture of β-sitosterol and stigmasterol (3), β-sitosterol glucoside (4), isovanillic acid (5), vanillic acid (6), and p-hydroxybenzoic acid (7). The structures of the isolated compounds were determined on the basis of physical and spectroscopic analyses, including 1D and 2D NMR (¹H, ¹³C, COSY, HSQC and HMBC) and mass spectrometry (HR-ESI-MS).     

Biotransformation of ent-pimaradienoic acid by cell cultures of Aspergillus niger

Microbial transformation stands out among the many possible semi-synthetic strategies employed to increase the variety of chemical structures that can be applied in the search for novel bioactive compounds. In this paper we obtained ent-pimaradienoic acid (1, PA, ent-pimara-8(14),15-dien-19-oic acid) derivatives by fungal biotransformation using Aspergillus niger strains. To assess the ability of such compounds to inhibit vascular smooth muscle contraction, we also investigated their spasmolytic effect, along with another five PA derivatives previously obtained in our laboratory, on aortic rings isolated from male Wistar rats. The microbial transformation experiments were conducted at 30 °C using submerged shaken liquid culture (120 rpm) for 10 days. One known compound, 7α-hydroxy ent-pimara-8(14),15-dien-19-oic acid (2), and three new derivatives, 1β-hydroxy ent-pimara-6,8(14),15-trien-19-oic acid (3), 1α,6β,14β-trihydroxy ent-pimara-7,15-dien-19-oic acid (4), and 1α,6β,7α,11α-tetrahydroxy ent-pimara-8(14),15-dien-19-oic acid (5), were isolated and identified on the basis of spectroscopic analyses and computational studies. The compounds obtained through biotransformation (2–5) did not display a significant antispasmodic activity (values ranging from 0% to 16.8% of inhibition); however the previously obtained diterpene, methyl 7α-hydroxy ent-pimara-8(14),15-dien-19-oate (8), showed to be very effective (82.5% of inhibition). In addition, our biological results highlight the importance to study the antispasmodic potential of a large number of novel diterpenes, to conduct further structure–activity relationship investigations.     

Fatty acid derivatives and dammarane triterpenes from the glandular trichome exudates of Ibicella lutea and Proboscidea louisiana

Ibicella lutea and Proboscidea louisiana, both of the Martyniaceae family, are known for rich glandular trichomes on their leaves and stems. Chemical investigations of the glandular trichome exudates on leaves of the two plants furnished three types of secondary metabolites, glycosylated fatty acids, glycerides (2-O-(3,6-diacetyloxyfattyacyl)glycerols and 2-O-(3-acetyloxyfattyacyl)glycerols) and dammarane triterpenes. The glycosylated fatty acids from I. lutea were determined to be 6(S)-(6-O-acetyl-β-d-glucopyranosyloxy)-octadecanoic acid (1A), -eicosanoic acid (1B) and -docosanoic acid (1C), as well as their respective deacetyl congeners (2A, 2B and 2C), whereas P. louisiana furnished 8(S)-(6-O-acetyl-β-d-glucopyranosyloxy)-eicosanoic acid (3A) and -docosanoic acid (3B) and their respective deacetyl congeners (4A and 4B), together with 2B. Both plants contained 12 identical 2-O-[(3R,6S)-3,6-diacetyloxyfattyacyl]glycerols (5A-L), in which the fatty acyl moieties contained between 17 and 21 carbon atoms. The corresponding mono-acetyloxy compounds, 2-O-[(3R)-3-acetyloxyfattyacyl]glycerols (6A–L) were detected in both plants. Among these glycerides, ten compounds (5A, 5C, 5F, 5H, 5K, 6A, 6C, 6F, 6H and 6K) had iso-fattyacyl structures and four (5E, 5J, 6E and 6J) had anteiso-fattyacyl structures. A previously unknown dammarane triterpene, betulatriterpene C 3-acetate (7), was isolated together with three known dammarane triterpenes, 24-epi-polacandrin 1,3-diacetate (8), betulatriterpene C (9) and 24-epi-polacandrin 3-acetate (10) from I. lutea, whereas 12 dammarane triterpenes, named probosciderols A–L (12–23), and the known compound betulafolienetriol (11) were isolated from P. louisiana. The structures of these compounds were elucidated by spectroscopic analysis including 2D-NMR techniques and chemical transformations. The 6-O-acetylglucosyloxy-fatty acids 1A–C (42%) and the dammarane triterpenes 7–10 (31%) were the two most abundant constituents in the glandular trichome exudate of I. lutea, whereas the dammarane triterpenes 11–23 (47%) and the glucosyloxy-fatty acids (4A, 4B and 2B) (38%) were the most abundant constituents in the glandular trichome exudate of P. louisiana.