Eremane, viscidane and isozizaene diterpenoids from the leaves of Eremophila rigida and their absolute configurations.

Previously undescribed eremane, viscidane, and isozizaene diterpenoids, eremorigidanes A-F, along with six known O-methylated flavonoids and three known triterpenoids were isolated and identified from the leaves of Eremophila rigida Chinnock by combined use of high-resolution PTP1B inhibition profiling, semipreparative- and analytical-scale HPLC separations, HPLC-PDA-HRMS analysis, and NMR spectroscopy. The absolute configuration of the unreported diterpenoids were determined by comparison of their experimental and calculated ECD spectra as well as by biosynthetic arguments. All isolates were evaluated for their PTP1B inhibitory activities, which revealed the flavonoid penduletin (3) to show inhibition with an IC50 value of 18.3 µM, and the triterpenoids 3,4-seco-olean-12-ene-3,28-dioic acid (15), oleanolic acid (16), and 3-oxo-oleanolic acid (17) to show inhibition with IC50 values of 55.7, 9.9, and 6.3 µM, respectively. The preliminary structure-activity relationship (SAR) of isolated flavonoids and triterpenoids is discussed. Plausible biosynthetic steps involved in eremane and isozizaene metabolism are presented and discussed.

Orthogonal Reversed-Phase C18 and Pentafluorophenyl HPLC Separation for Phytochemical Profiling of Serrulatanes in Eremophila denticulata.

Serrulatanes constitute a class of unique diterpenoids derived from all-Z nerylneryl diphosphate rather than the conventional all-E diterpenoid precursor geranylgeranyl diphosphate and thus provide an intriguing expansion of the chemical space of plant specialized metabolites. Plants of the Australian Eremophila genus are rich sources of structurally diverse serrulatanes. Here, we report the identification of 15 hitherto undescribed serrulatanes (eremoculatanes A-N), together with 16 previously reported compounds, from the EtOAc extract of Eremophila denticulata leaves. Isolation was performed by a combined use of systematic HPLC-PDA-HRMS-based phytochemical profiling and orthogonal reversed-phase C18 and pentafluorophenyl separations. Among the new compounds isolated, eremoculatane A contains a C12 backbone, for which the configuration was established by comparison of experimentally measured and theoretically calculated ECD spectra. The antihyperglycemic and antibacterial activities of the E. denticulata extract were investigated by high-resolution inhibition profiling, and they indicated that major constituents, mainly serrulatanes and flavonoids, contributed to the observed activity of the extract. One flavonoid, eupafolin (4), displayed moderate α-glucosidase inhibitory activity with an IC50 value of 41.3 µM, and four serrulatanes (8, 9, 19g, and 19j) showed more than 50% PTP1B inhibition at 200 µM.

Neuroprotection against Aluminum Chloride-Induced Hippocampus Damage in Albino Wistar Rats by Leucophyllum frutescens (Berl.) I.M. Johnst. Leaf Extracts: A Detailed Insight into Phytochemical Analysis and Antioxidant and Enzyme Inhibition Assays.

BACKGROUND: A previously unstudied medicinal plant, Leucophyllum frutescens (Berland.) I.M. Johnst. (Scrophulariaceae) was investigated to evaluate its potential in preventing and treating neurodegenerative diseases, including Alzheimer's disease. METHODS: Methanolic leaf extract (MELE) and its fractions (HELE, CHLE, and BULE) were evaluated for their polyphenolic content and antioxidant activity by five different methods, including in vitro enzyme inhibition assays, which are clinically linked to neurodegenerative diseases. The potentially active n-butanol fraction (BULE) was further evaluated for its neuroprotective effects using an albino rat animal model and phytoconstituents profiling using Liquid chromatography with tandem mass spectrometry (LC-MS/MS), and in silico molecular docking by Maestro® Schrödinger. RESULTS: The n-butanol fraction (BULE) in the hydroalcoholic leaf extract exhibited the highest total phenolic content (230.435 ± 1.575 mg gallic acid equivalent gm-1± SD). The chloroform leaf extract exhibited the highest total flavonoid content (293.343 ± 3.756 mg quercetin equivalent gm-1± SD) as well as the highest antioxidant content, which was equivalent to Trolox, with five assay methods. Similarly, the chloroform and n-butanol fractions from the hydroalcoholic leaf extract significantly inhibited human acetylcholinesterase and butyrylcholinesterase with their IC50 values of 12.14 ± 0.85 and 129.73 ± 1.14 µg∙mL-1, respectively. The in vivo study revealed that BULE exhibited a significant neuroprotective effect at doses of 200 and 400 mg/kg/day in an aluminum chloride-induced neurodegenerative albino rat model. The LC-MS/MS analysis of BULE tentatively confirmed the presence of biologically active secondary metabolites, such as theobromine, propyl gallate, quercetin-3-O-glucoside, myricetin-3-acetylrhamnoside, isoquercitrin-6'-O-malonate, diosmetin-7-O-glucuronide-3'-O-pentose, pinoresinol diglucoside, asarinin, eridictoyl, epigallocatechin, methyl gallate derivative, and eudesmin. The results from the computational molecular docking of the identified secondary metabolites revealed that diosmetin-7-O-glucuronide-3'-O-pentose had the highest binding affinity to human butyrylcholinesterase, while isoquercetin-6'-O-malonate had the highest to human acetylcholinesterase, and pinoresinol diglucoside to human salivary alpha-amylase. CONCLUSIONS: The present study concluded a need for further exploration into this medicinal plant, including the isolation of the bioactive compounds responsible for its neuroprotective effects.

Characterization and Comparative Analysis of Chloroplast Genomes of Medicinal Herb Scrophularia ningpoensis and Its Common Adulterants (Scrophulariaceae).

Scrophularia ningpoensis, a perennial medicinal plant from the Scrophulariaceae family, is the original species of Scrophulariae Radix (SR) in the Chinese Pharmacopoeia. This medicine is usually deliberately substituted or accidentally contaminated with other closely related species including S. kakudensis, S. buergeriana, and S. yoshimurae. Given the ambiguous identification of germplasm and complex evolutionary relationships within the genus, the complete chloroplast genomes of the four mentioned Scrophularia species were sequenced and characterized. Comparative genomic studies revealed a high degree of conservation in genomic structure, gene arrangement, and content within the species, with the entire chloroplast genome spanning 153,016-153,631 bp in full length, encoding 132 genes, including 80 protein-coding genes, 4 rRNA genes, 30 tRNA genes, and 18 duplicated genes. We identified 8 highly variable plastid regions and 39-44 SSRs as potential molecular markers for further species identification in the genus. The consistent and robust phylogenetic relationships of S. ningpoensis and its common adulterants were firstly established using a total of 28 plastid genomes from the Scrophulariaceae family. In the monophyletic group, S. kakudensis was determined to be the earliest diverging species, succeeded by S. ningpoensis. Meanwhile, S. yoshimurae and S. buergeriana were clustered together as sister clades. Our research manifestly illustrates the efficacy of plastid genomes in identifying S. ningpoensis and its counterfeits and will also contribute to a deeper understanding of the evolutionary processes within Scrophularia.

Phylogenomics sheds new light on the drivers behind a long-lasting systematic riddle: the figwort family Scrophulariaceae.

The figwort family, Scrophulariaceae, comprises c. 2000 species whose evolutionary relationships at the tribal level have proven difficult to resolve, hindering our ability to understand their origin and diversification. We designed a specific probe kit for Scrophulariaceae, targeting 849 nuclear loci and obtaining plastid regions as by-products. We sampled c. 87% of the genera described in the family and use the nuclear dataset to estimate evolutionary relationships, timing of diversification, and biogeographic patterns. Ten tribes, including two new tribes, Androyeae and Camptolomeae, are supported, and the phylogenetic positions of Androya, Camptoloma, and Phygelius are unveiled. Our study reveals a major diversification at c. 60 million yr ago in some Gondwanan landmasses, where two different lineages diversified, one of which gave rise to nearly 81% of extant species. A Southern African origin is estimated for most modern-day tribes, with two exceptions, the American Leucophylleae, and the mainly Australian Myoporeae. The rapid mid-Eocene diversification is aligned with geographic expansion within southern Africa in most tribes, followed by range expansion to tropical Africa and multiple dispersals out of Africa. Our robust phylogeny provides a framework for future studies aimed at understanding the role of macroevolutionary patterns and processes that generated Scrophulariaceae diversity.

Characterization of Serrulatane Diterpenoids in Eremophila phyllopoda subsp. phyllopoda by Triple High-Resolution α-Glucosidase/PTP1B/Radical Scavenging Profiling, NMR Spectroscopy, DFT-GIAO NMR, and Electronic Circular Dichroism Calculations.

Extracts of Eremophila phyllopoda subsp. phyllopoda showed α-glucosidase and PTP1B inhibitory activity with IC50 values of 19.6 and 13.6 µg/mL, respectively. High-resolution α-glucosidase/PTP1B/radical scavenging profiling was performed to establish a triple high-resolution inhibition profile that allowed direct pinpointing of the constituents responsible for one or more of the observed bioactivities. Subsequent targeted isolation and purification by analytical-scale HPLC led to the identification of 21 previously undescribed serrulatane diterpenoids, eremophyllanes A-U, as well as two known serrulatane diterpenoids, 1ß-trihydroxyserrulatane (8) and 1α-trihydroxyserrulatane (10d), and five known furofuran lignans, (+)-piperitol (6), horsfieldin (7e), (-)-sesamin (9), (+)-sesamin (10h), and asarinin (10i). Their structures were elucidated by extensive analysis of HRMS and 1D and 2D NMR spectroscopic data. The relative configurations of the previously undescribed compounds were established by analysis of ROESY spectra as well as by DFT-GIAO NMR calculations followed by DP4+ probability analysis. The absolute configurations were determined by comparison of experimental and calculated ECD spectra. Serrulatane diterpenoids 7b and 14 exhibited α-glucosidase inhibitory activity with IC50 values of 28.4 and 64.2 µM, respectively, while 11, 12, 14, and 15 exhibited PTP1B inhibitory activity with IC50 values ranging from 16.6 to 104.6 µM. Hypothetical routes for formation of all identified serrulatane diterpenoids are proposed.

Deciphering complex reticulate evolution of Asian Buddleja (Scrophulariaceae): insights into the taxonomy and speciation of polyploid taxa in the Sino-Himalayan region.

BACKGROUND AND AIMS: Species of the genus Buddleja in Asia are mainly distributed in the Sino-Himalayan region and form a challenging taxonomic group, with extensive hybridization and polyploidization. A phylogenetic approach to unravelling the history of reticulation in this lineage will deepen our understanding of the speciation in biodiversity hotspots. METHODS: For this study, we obtained 80 accessions representing all the species in the Asian Buddleja clade, and the ploidy level of each taxon was determined by flow cytometry analyses. Whole plastid genomes, nuclear ribosomal DNA, single nucleotide polymorphisms and a large number of low-copy nuclear genes assembled from genome skimming data were used to investigate the reticulate evolutionary history of Asian Buddleja. Complex cytonuclear conflicts were detected through a comparison of plastid and species trees. Gene tree incongruence was also analysed to detect any reticulate events in the history of this lineage. KEY RESULTS: Six hybridization events were detected, which are able to explain the cytonuclear conflict in Asian Buddleja. Furthermore, PhyloNet analysis combining species ploidy data indicated several allopolyploid speciation events. A strongly supported species tree inferred from a large number of low-copy nuclear genes not only corrected some earlier misinterpretations, but also indicated that there are many Asian Buddleja species that have been lumped mistakenly. Divergent time estimation shows two periods of rapid diversification (8-10 and 0-3 Mya) in the Asian Buddleja clade, which might coincide with the final uplift of the Hengduan Mountains and Quaternary climate fluctuations, respectively. CONCLUSIONS: This study presents a well-supported phylogenetic backbone for the Asian Buddleja species, elucidates their complex and reticulate evolutionary history and suggests that tectonic activity, climate fluctuations, polyploidization and hybridization together promoted the diversification of this lineage.

Bioactivity evaluation of least explored traditionally acclaimed medicinally potent herb Nanorrhinum ramosissimum(Wall. ) Betsche

Abstract Present study analysed the therapeutic potential of traditionally acclaimed medicinal herb Nanorrhinum ramosissimum, using plant parts extracted with different solvents (10 mg/mL). Shoot extracts exhibited comparatively better antimicrobial properties, in comparison to root extracts. Total phenolic content was estimated, to ascertain its dependency on antioxidant properties of plant extracts. Antioxidant assay revealed promising results in comparison to IC50 value of standard ascorbic acid (52.2±0.07 µg/mL), for methanolic extracts of shoot (61.07±0.53 µg/mL and 64.33±0.33 µg/mL) and root (76.705±0.12 µg/mL and 89.73±0.28 µg/ mL) for in vivo and in vitro regenerants respectively. Correlation coefficient R2 values ranged between 0.90-0.95, indicating a positive correlation between phenolic contents and antioxidant activity. Plant extracts were also able to inhibit DNA oxidative damage again indicating their antioxidative potential. Antidiabetic potential was confirmed by alpha amylase inhibition assay where shoot methanolic extracts (invivo, in vitro) exhibited the best IC50 values (54.42±0.16 µg/mL, 66.09±0.12 µg/mL) in comparison to standard metformin (41.92±0.08 µg/mL). Ethanolic extracts of roots (in vitro, invivo) exhibited the relative IC50 values (88.97±0.32µg/mL,96.63±0.44 µg/mL) indicating that shoot parts had a better alpha amylase inhibition property; thus proving the herb's bioactive potential and its prospective therapeutic source for curing various ailments.

Phytochemistry, Medicinal Properties, Bioactive Compounds, and Therapeutic Potential of the Genus Eremophila (Scrophulariaceae).

The genus Eremophila (family Scrophulariaceae) consists of approximately 200 species that are widely distributed in the semi-arid and arid regions of Australia. Multiple Eremophila spp. are used as traditional medicines by the First Australians in the areas in which they grow. They are used for their antibacterial, antifungal, antiviral, antioxidant, anti-diabetic, anti-inflammatory, and cardiac properties. Many species of this genus are beneficial against several diseases and ailments. The antibacterial properties of the genus have been relatively well studied, with several important compounds identified and their mechanisms studied. In particular, Eremophila spp. are rich in terpenoids, and the antimicrobial bioactivities of many of these compounds have already been confirmed. The therapeutic properties of Eremophila spp. preparations and purified compounds have received substantially less attention, and much study is required to validate the traditional uses and to highlight species that warrant further investigation as drug leads. The aim of this study is to review and summarise the research into the medicinal properties, therapeutic mechanisms, and phytochemistry of Eremophila spp., with the aim of focussing future studies into the therapeutic potential of this important genus.

Comparative and Phylogenetic Analyses of Complete Chloroplast Genomes of Scrophularia incisa Complex (Scrophulariaceae).

The Scrophularia incisa complex is a group of closely related desert and steppe subshrubs that includes S. incisa, S. kiriloviana and S. dentata, which are the only S. sect. Caninae components found in Northwest China. Based on earlier molecular evidence, the species boundaries and phylogenetic relationships within this complex remain poorly resolved. Here, we characterized seven complete chloroplast genomes encompassing the representatives of the three taxa in the complex and one closely related species, S. integrifolia, as well as three other species of Scrophularia. Comparative genomic analyses indicated that the genomic structure, gene order and content were highly conserved among these eleven plastomes. Highly variable plastid regions and simple sequence repeats (SSRs) were identified. The robust and consistent phylogenetic relationships of the S. incisa complex were firstly constructed based on a total of 26 plastid genomes from Scrophulariaceae. Within the monophyletic complex, a S. kiriloviana individual from Pamirs Plateau was identified as the earliest diverging clade, followed by S. dentata from Tibet, while the remaining individuals of S. kiriloviana from the Tianshan Mountains and S. incisa from Qinghai-Gansu were clustered into sister clades. Our results evidently demonstrate the capability of plastid genomes to improve phylogenetic resolution and species delimitation, particularly among closely related species, and will promote the understanding of plastome evolution in Scrophularia.

Serrulatane diterpenoids with unusual side chain modifications from root bark of Eremophila longifolia.

The plant genus Eremophila is endemic to Australia and widespread in arid regions. Root bark extract of Eremophila longifolia (R.Br.) F.Muell. (Scrophulariaceae) was investigated by LC-PDA-HRMS, and dereplication suggested the presence of a series of diterpenoids. Using a combination of preparative- and analytical-scale HPLC separation as well as extensive 1D and 2D NMR analysis, the structures of 12 hitherto unreported serrulatane diterpenoids, eremolongine A-L, were established. These structures included serrulatanes with unusual side chain modifications to form hitherto unseen skeletons with, e.g., cyclopentane, oxepane, and bicyclic hexahydro-1H-cyclopenta[c]furan moieties. Serrulatane diterpenoids in Eremophila have recently been shown to originate from a common biosynthetic precursor with conserved stereochemical configuration, and this was used for tentative assignment of the relative and absolute configuration of the isolated compounds. Triple high-resolution α-glucosidase/α-amylase/PTP1B inhibition profiling demonstrated that several of the eremolongines had weak inhibitory activity towards targets important for management of type 2 diabetes.

Taxonomic review of Manulea (M.) tienmushanica (Daniel), comb. nov., and its allies with descriptions of two new species from mainland China (Lepidoptera: Erebidae: Arctiinae).

The Manulea tienmushanica (Daniel, 1954) species group is established, characterised and reviewed. Two new species are described: Manulea (M.) salweena sp. n. (China: Yunnan), and Manulea (M.) diaforetica sp. n. (China: Yunnan). Two new combinations are established: Manulea (M.) tienmushanica (Daniel, 1954), comb. n. and Manulea (M.) nigripuncta (Fang, 2000), comb. n. Adults, male and female genitalia are illustrated.

Taxonomy, comparative genomics of Mullein (Verbascum, Scrophulariaceae), with implications for the evolution of Verbascum and Lamiales.

BACKGROUND: The genus Verbascum L. (Scrophulariaceae) is distributed in Africa, Europe, and parts of Asia, with the Mediterranean having the most species variety. Several researchers have already worked on the phylogenetic and taxonomic analysis of Verbascum by using ITS data and chloroplast genome fragments and have produced different conclusions. The taxonomy and phylogenetic relationships of this genus are unclear. RESULTS: The complete plastomes (cp) lengths for V. chaixii, V. songaricum, V. phoeniceum, V. blattaria, V. sinaiticum, V. thapsus, and V. brevipedicellatum ranged from 153,014 to 153,481 bp. The cp coded 114 unique genes comprising of 80 protein-coding genes, four ribosomal RNA (rRNA), and 30 tRNA genes. We detected variations in the repeat structures, gene expansion on the inverted repeat, and single copy (IR/SC) boundary regions. The substitution rate analysis indicated that some genes were under purifying selection pressure. Phylogenetic analysis supported the sister relationship of (Lentibulariaceae + Acanthaceae + Bignoniaceae + Verbenaceae + Pedaliaceae) and (Lamiaceae + Phyrymaceae + Orobanchaceae + Paulowniaceae + Mazaceae) in Lamiales. Within Scrophulariaceae, Verbascum was sister to Scrophularia, while Buddleja formed a monophyletic clade from (Scrophularia + Verbascum) with high bootstrap support values. The relationship of the nine species within Verbascum was highly supported. CONCLUSION: Based on the phylogenetic results, we proposed to reinstate the species status of V. brevipedicellatum (Engl.) Hub.-Mor. Additionally, three genera (Mazus, Lancea, and Dodartia) placed in the Phyrymaceae family formed a separate clade within Lamiaceae. The classification of the three genera was supported by previous studies. Thus, the current study also suggests the circumscription of these genera as documented previously to be reinstated. The divergence time of Lamiales was approximated to be 86.28 million years ago (Ma) (95% highest posterior density (HPD), 85.12-89.91 Ma). The complete plastomes sequence data of the Verbascum species will be important for understanding the Verbascum phylogenetic relationships and evolution in order Lamiales.

Biodiscoveries within the Australian plant genus Eremophila based on international and interdisciplinary collaboration: results and perspectives on outstanding ethical dilemmas.

In a cross-continental research initiative, including researchers working in Australia and Denmark, and based on joint external funding by a 3-year grant from the Novo Nordisk Foundation, we have used DNA sequencing, extensive chemical profiling and molecular networking analyses across the entire Eremophila genus to provide new knowledge on the presence of natural products and their bioactivities using polypharmocological screens. Sesquiterpenoids, diterpenoids and dimers of branched-chain fatty acids with previously unknown chemical structures were identified. The collection of plant material from the Eremophila genus was carried out according to a 'bioprospecting agreement' with the Government of Western Australia. We recognize that several Eremophila species hold immense cultural significance to Australia's First Peoples. In spite of our best intentions to ensure that new knowledge gained about the genus Eremophila and any potential future benefits are shared in an equitable manner, in accordance with the Nagoya Protocol, we encounter serious dilemmas and potential conflicts in making benefit sharing with Australia's First Peoples a reality.

Serrulatane diterpenoids from the leaves of Eremophila glabra and their potential as antihyperglycemic drug leads.

Eremophila (Scrophulariaceae) is a genus of Australian desert plants, which have been used by Australian Aboriginal people for various medicinal purposes. Crude extracts of the leaf resin of Eremophila glabra (R.Br.) Ostenf. showed α-glucosidase and protein tyrosine phosphatase 1B (PTP1B) inhibitory activity with IC50 values of 19.3 ± 1.2 µg/mL and 11.8 ± 2.1 µg/mL, respectively. Dual α-glucosidase/PTP1B high-resolution inhibition profiling combined with HPLC-PDA-HRMS and NMR were used to isolate and identify the compounds providing these activities. This resulted in isolation of seven undescribed serrulatane diterpenoids, eremoglabrane A-G, together with nine previously identified serrulatane diterpenoids and flavonoids. Three of the serrulatane diterpenoids showed PTP1B inhibitory activities with IC50 values from 63.8 ± 5.8 µM to 104.5 ± 25.9 µM.

The hypothesis of tautomeric equilibrium between epimers in ciquitins A and B.

Recently, ciquitins A and B isolated from the powdered and defatted airdried aerial parts of Leucophyllum ambiguum were reported as a mixture of conformers in a solution at room temperature. Considering the existence of a hemiacetal hydroxyl fragment in the ciquitins A and B, they are more likely to exist in the form of epimer rather than the mixture of conformers. To confirm this hypothesis, the NMR calculations of two epimers at C-9 (1-a and 1-b) were performed and the results matched well with experimental NMR data of mixtures (1). Moreover, a brief discussion on the reason for this hypothesis was also presented.

Essential oils from the leaves and flowers of Leucophyllum frutescens (Scrophulariaceae): phytochemical analysis and inhibitory effects against elastase and collagenase in vitro.

Leucophyllum frutescens (Scrophulariaceae) is a medicinal plant of Mexican traditional medicine. The aim of this study was to analyse the volatile components from the leaves and flowers by GC/MS and to assess their anti-aging activity for the first time. A total of 30 compounds were identified where 1-octen-3-ol (73.56%) and D-limonene (11.12%) represented the major ingredients in the leaves, while n-heneicosane (32.30%) and dehydroepingaione (15.15%) were the major components in the flowers. In vitro anti-aging activity was measured via assessing collagenase and elastase inhibition. Essential oils from the leaves and flowers showed potential collagenase inhibitory activity with IC50 of 55.7 and 47.4 µg/mL. However, the oils from the leaves and flowers showed moderate anti-elastase activity with IC50 of 60.8 and 97.7 µg/mL. Therefore, the oil of Leucophyllum frutescens could afford a promising natural anti-aging drug.

Phytochemical Analysis and Anti-Inflammatory and Anti-Osteoarthritic Bioactive Potential of Verbascum thapsus L. (Scrophulariaceae) Leaf Extract Evaluated in Two In Vitro Models of Inflammation and Osteoarthritis.

Osteoarthritis (OA) is a complex disease, source of pain and disability that affects millions of people worldwide. OA etiology is complex, multifactorial and joint-specific, with genetic, biological and biomechanical components. Recently, several studies have suggested a potential adjuvant role for natural extracts on OA progression, in terms of moderating chondrocyte inflammation and following cartilage injury, thus resulting in an overall improvement of joint pain. In this study, we first analyzed the phenylethanoid glycosides profile and the total amount of polyphenols present in a leaf aqueous extract of Verbascum thapsus L. We then investigated the anti-inflammatory and anti-osteoarthritic bioactive potential of the extract in murine monocyte/macrophage-like cells (RAW 264.7) and in human chondrocyte cells (HC), by gene expression analysis of specifics inflammatory cytokines, pro-inflammatory enzymes and metalloproteases. Six phenylethanoid glycosides were identified and the total phenolic content was 124.0 ± 0.7 mg gallic acid equivalent (GAE)/g of extract. The biological investigation showed that the extract is able to significantly decrease most of the cellular inflammatory markers, compared to both control cells and cells treated with Harpagophytum procumbens (Burch.) DC. ex Meisn, used as a positive control. Verbascum thapsus leaf aqueous extract has the potential to moderate the inflammatory response, representing an innovative possible approach for the inflammatory joint disease treatment.

Design, synthesis and screening of a drug discovery library based on an Eremophila-derived serrulatane scaffold.

Chemical studies of the aerial parts of the Australian desert plant Eremophila microtheca afforded the targeted and known diterpenoid scaffolds, 3,7,8-trihydroxyserrulat-14-en-19-oic acid and 3-acetoxy-7,8-dihydroxyserrulat-14-en-19-oic acid. The most abundant serrulatane scaffold was converted to the poly-methyl derivatives, 3-hydroxy-7,8-dimethoxyserrulat-14-en-19-oic acid methyl ester and 3,7,8-trimethoxyserrulat-14-en-19-oic acid methyl ester using simple and rapid methylation conditions consisting of DMSO, NaOH and MeI at room temperature. Subsequently a 12-membered amide library was synthesised by reacting the methylated scaffolds with a diverse series of commercial primary amines. The chemical structures of the 12 undescribed semi-synthetic analogues were fully characterised following 1D/2D NMR, MS, UV, ECD and [α]D data analyses. All compounds were evaluated for their anthelmintic, anti-microbial and anti-viral activities. While none of the compounds significantly inhibited motility or development of the exsheathed third-stage larvae (xL3s) of a pathogenic ruminant parasite, Haemonchus contortus, the tri-methylated analogue induced a skinny phenotype in fourth-stage larvae (L4s) after seven days of treatment (IC50 = 14 µM). Anti-bacterial and anti-fungal activities were not observed at concentrations up to 20 µM. Activity against HIV latency reversal was tested in inducible, chronically-infected cells, with the tri-methylated analogue being the most active (EC50 = 38 µM).