Lysinibacillus Isolate MK212927: A Natural Producer of Allylamine Antifungal ‘Terbinafine’

Resistance to antifungal agents represents a major clinical challenge, leading to high morbidity and mortality rates, especially in immunocompromised patients. In this study, we screened soil bacterial isolates for the capability of producing metabolites with antifungal activities via the cross-streak and agar cup-plate methods. One isolate, coded S6, showed observable antifungal activity against Candida (C.) albicans ATCC 10231 and Aspergillus (A.) niger clinical isolate. This strain was identified using a combined approach of phenotypic and molecular techniques as Lysinibacillus sp. MK212927. The purified metabolite displayed fungicidal activity, reserved its activity in a relatively wide range of temperatures (up to 60 °C) and pH values (6–7.8) and was stable in the presence of various enzymes and detergents. As compared to fluconazole, miconazole and Lamisil, the minimum inhibitory concentration of the metabolite that showed 90% inhibition of the growth (MIC90) was equivalent to that of Lamisil, half of miconazole and one fourth of fluconazole. Using different spectroscopic techniques such as FTIR, UV spectroscopy, 1D NMR and 2D NMR techniques, the purified metabolite was identified as terbinafine, an allylamine antifungal agent. It is deemed necessary to note that this is the first report of terbinafine production by Lysinibacillus sp. MK212927, a fast-growing microbial source, with relatively high yield and that is subject to potential optimization for industrial production capabilities.

Theonellamides J and K and 5-cis-Apoa-theopalauamide, Bicyclic Glycopeptides of the Red Sea Sponge Theonella swinhoei

Theonella swinhoei is a fairly common inhabitant of reefs throughout the Indian and Pacific Oceans. Metabolomic analyses of samples of T. swinhoei collected in different depths in the Gulf of Aqaba revealed two chemotypes differing in the profiles of the theonellamides they produce, some of which seem to be unknown. Driven by this finding, we examined a sample of T. swinhoei collected more than 40 years ago in the southern part of the Gulf of Aqaba. Large-scale extract of this sample yielded four theonellamides, the known theopalauamide (4), as the major component, and three new metabolites, theonellamide J (1), 5-cis-Apoa-theopalauamide (2), and theonellamide K (3), as the minor components. The planar structure of these complex cyclic glycopeptides was elucidated by combination of 1D and 2D NMR techniques and HRESIMS. The absolute configuration of the amino acids was established by Marfey’s and advanced Marfey’s methods, and the absolute configuration of its galactose unit using “Tanaka’s method” for monosaccharides. The biological activity of the pure compounds was tested for antibacterial activity and for cytotoxicity to HTC-116 cell line. The compounds presented significant cytotoxicity against the HTC-116 cell line, illuminating the importance of the Apoa subunit for the activity.

Pharmacognostic Study on Elsholtzia ciliata (Thumb.) Hyl: Anatomy, Phytochemistry and Pharmacological Activities

Elsholtzia ciliata (Thunb.) Hyl, family Lamiaceae, is an important and popular anti-bacterial and anti-inflammatory Traditional Chinese Medicine (TCM). However, there are limited scientific studies on its anatomy and pharmacological activities. Moreover, the information of chemical constituents in relation to its non-volatile constituents are still missing. The current study aimed to evaluate the anatomic, pharmacological and phytochemical profile of Elsholtzia ciliata, providing means for the quality control of this herbal drug. The methodology designed for this study included the preparation of anatomic sections and their description, extraction, chromatography, structural elucidation of isolated compounds by NMR techniques and their quantification by HPLC using pharmacological assays (Formalin, hot plate, DPPH, antimicrobial-Gram positive, Gram Negative and fungus, and MTT assays) to confirm the activities described for this species. Results of the anatomic study are aligned with the pattern expected for plants belonging to the Lamiaceae family; Ursolic acid and Oroxylin were isolated from this plant species. The findings observed in this study indicate that Elsholtzia ciliata possess anti-inflammatory, antinociceptive, antioxidant, antimicrobial and anticancer activities. The chemical compounds isolated from its leaves and the anatomy profile of its parts provide the basis for further quality control for this plant.

Efficacy of Precocene I from Desmosstachya bipinnata as an Effective Bioactive Molecules against the Spodoptera litura Fab. and Its Impact on Eisenia fetida Savigny

The sustainability of agroecosystems are maintained with agro-chemicals. However, after more than 80 years of intensive use, many pests and pathogens have developed resistance to the currently used chemistries. Thus, we explored the isolation and bioactivity of a chemical compound, Precocene I, isolated from the perennial grass, Desmosstachya bipinnata (L.) Stapf. Fractions produced from chloroform extractions showed suppressive activity on larvae of Spodoptera litura (Lepidoptera: Noctuidae), the Oriental armyworm. Column chromatography analyses identified Precocene I confirmed using FTIR, HPLC and NMR techniques. The bioactivity of the plant-extracted Dp-Precocene I was compared to a commercially produced Precocene I standard. The percentage of mortality observed in insects fed on plant tissue treated with 60 ppm Db-Precocene I was 97, 87 and 81, respectively, for the second, third and fourth instar larvae. The LC50 value of third instars was 23.2 ppm. The percentages of survival, pupation, fecundity and egg hatch were altered at sub-lethal concentrations of Db-Precocene I (2, 4, 6 and 8 ppm, sprays on castor leaves). The observed effects were negatively correlated with concentration, with a decrease in effects as concentrations increased. Distinct changes in feeding activity and damage to gut tissues were observed upon histological examination of S. litura larvae after the ingestion of Db-Precocene I treatments. Comparative analyses of mortality on a non-target organism, the earthworm, Eisenia fetida, at equal concentrations of Precocene I and two chemical pesticides (cypermethrin and monocrotophos) produced mortality only with the chemical pesticide treatments. These results of Db-Precocene I as a highly active bioactive compound support further research to develop production from the grass D. bipinnata as an affordable resource for Precocene-I-based insecticides.

Detecting Organic Nitrogen with 1H-15N HMBC Spectra

NMR spectroscopy has been the most important tool for organic chemistry research, providing detailed structure information. While 1H and 13C NMR spectra were frequently measured, 15N NMR spectra were relatively rare, even though nitrogen is commonly observed in organic molecules. This is due to the low gyromagnetic ratio and nature abundance. Usually 15N NMR spectra are observed when the sample is in very high concentration or the nitrogen is enriched with 15N isotope. HMBC is one of the 2D NMR techniques, measuring the through-bond correlations inside a molecule. 1H-15N HMBC actually collects a series of measurements of 1H NMR spectra with 15N information. Therefore, HMBC could get stronger signals than 15N signals and provide the opportunity for the indirect measurement of 15N signals.

Identification of Salicylates in Willow Bark (Salix Cortex) for Targeting Peripheral Inflammation

Salix cortex-containing medicine is used against pain conditions, fever, headaches, and inflammation, which are partly mediated via arachidonic acid-derived prostaglandins (PGs). We used an activity-guided fractionation strategy, followed by structure elucidation experiments using LC-MS/MS, CD-spectroscopy, and 1D/2D NMR techniques, to identify the compounds relevant for the inhibition of PGE2 release from activated human peripheral blood mononuclear cells. Subsequent compound purification by means of preparative and semipreparative HPLC revealed 2′-O-acetylsalicortin (1), 3′-O-acetylsalicortin (2), 2′-O-acetylsalicin (3), 2′,6′-O-diacetylsalicortin (4), lasiandrin (5), tremulacin (6), and cinnamrutinose A (7). In contrast to 3 and 7, compounds 1, 2, 4, 5, and 6 showed inhibitory activity against PGE2 release with different potencies. Polyphenols were not relevant for the bioactivity of the Salix extract but salicylates, which degrade to, e.g., catechol, salicylic acid, salicin, and/or 1-hydroxy-6-oxo-2-cycohexenecarboxylate. Inflammation presents an important therapeutic target for pharmacological interventions; thus, the identification of relevant key drugs in Salix could provide new prospects for the improvement and standardization of existing clinical medicine.

Proline residues impart a tripartite segmental behavior to the nucleosomal H3 histone tail in the unmodified and posttranslationally modified states

Histone tails are integral structural and functional components of the eukaryotic nucleosome. These tails, rich in positively charged amino acid residues, interact with the DNA to stabilize the nucleosomal structure. However, capturing the biochemical effects of posttranslational modifications (PTMs) on histone tails in molecular detail using X-ray or NMR techniques remains a challenge due to their intrinsically disordered structure. In this work, we studied the N-terminal portion of the H3 histone protein, a 38-residue tail, that when posttranslationally modified, is implicated in altering the tail’s interaction with the DNA, affecting nucleosomal stability. Using all-atom molecular dynamics simulations for a total of 35 microseconds, we investigated the structure and dynamics of the wildtype H3 tail and seven known nucleosomal PTMs. Based on residues’ contacts with DNA, water, and ions, dihedral angle analysis, and root-mean-square fluctuations of the tail residues, our results show that the H3 tail has a tripartite segmental nature. The three segments, labeled I, II, and III, are separated by the proline residues P16, P30, and P38. A comparison of wildtype H3 tail and proline-to-alanine-mutated H3 tail showed that the prolines function as segmental dividers or hinges of the H3 tail. We show that Segment I is more dynamic than Segments II and III, and Segment I makes multiple transient contacts with the DNA. The PTMs affect the tail’s dynamics to different extents, but the tripartite segmental nature of the tail is preserved. Notably, single-residue modification of the lysine by acetylation or methylations in Segment I versus multiple residue modifications by serine phosphorylation or lysine methylations have marked effects on the tail’s flexibility and interaction with the DNA. This study highlights the significance of proline residues in creating the segmental behavior of the H3 tail.