Scalarane-Type Sesterterpenoids from the Marine Sponge Lendenfeldia sp. Alleviate Inflammation in Human Neutrophils

Nor-24-homoscalaranes, Neutrophilic Inflammatory Mediators from the Marine Sponge Lendenfeldia sp

The marine sponge Lendenfeldia sp., collected from the Southern waters of Taiwan, was subjected to chemical composition screening, resulting in the isolation of four new 24-homoscalarane compounds, namely lendenfeldaranes R-U (1-4). The structures and relative stereochemistry of the new metabolites 1-4 were assigned based on NMR studies. The absolute configurations of compounds 1-4 were determined by comparing the calculated and experimental values of specific optical rotation. The antioxidant and anti-inflammatory activities of the isolated compounds were assayed using superoxide anion generation and elastase release assays. These assays are used to determine neutrophilic inflammatory responses of respiratory burst and degranulation. Compounds 2 and 4 inhibited superoxide anion generation by human neutrophils in response to formyl-L-methionyl-L-leucyl-L-phenylalanine/cytochalasin B (fMLP/CB) with IC50: 3.98-4.46 μM. Compounds 2 and 4 inhibited fMLP/CB-induced elastase release, with IC50 values ranging from 4.73 to 5.24 μM. These findings suggested that these new 24-homoscalarane compounds possess unique structures and potential anti-inflammatory activity.

Chemometric-guided chemical marker selection: A case study of the heat-clearing herb Scrophularia ningpoensis

The selection of medicinal plants' chemical markers focuses on bioactivity as the primary goal, followed by the nature of secondary metabolites, their stability, and availability. However, herbal medicines are valued for their complex and holistic pharmacological effects. A correct chemical marker can be carefully selected by a systematic clarification of their chemical-biological relationships. In the current study, the multi-informative molecular networking (MIMN) approach was employed to construct the anti-inflammatory metabolomic pattern of a heat-clearing herb, Scrophularia ningpoensis Hemsl. (S. ningpoensis). The MIMN molecular families characterized by cinnamic acid glycosides showed a higher bioactivity score compared with the other two major chemical classes (iridoid glycosides and iridoid-cinnamic acid glycosides). The Global Natural Product Social Molecular Networking (GNPS) and Reaxys database were used to assist in the putative annotation of eighteen metabolites from the bioactive and non-bioactive molecular families. The anti-inflammatory validation step was based on the detection of reactive oxygen species (ROS) generation by activated human neutrophils. All compounds from the bioactive MIMN molecular families dose-dependently inhibited the total ROS generation promoted by fMLF (IC₅₀: 0.04-0.42 μM), while the compounds from non-bioactive MIMN clusters did not show any significant anti-inflammatory effect. The ROS-dependent anti-inflammatory activity of these cinnamic acid glycosides was attributed to their oxygen radical scavenging ability. The most abundant cinnamic acid glycoside, angoroside C (IC₅₀: 0.34 μM) was suggested to be selected as a chemical marker for S. ningpoensis. In this study, the MIMN platform was applied to assist in the chemical marker selection of S. ningpoensis. The correct selection of markers will aid in the compilation and revision of herbal monographs and pharmacopeias resulting in the precise analysis and classification of medicinal plants on a scientific basis.

Marine natural products

Covering: January to December 2021This review covers the literature published in 2021 for marine natural products (MNPs), with 736 citations (724 for the period January to December 2021) referring to compounds isolated from marine microorganisms and phytoplankton, green, brown and red algae, sponges, cnidarians, bryozoans, molluscs, tunicates, echinoderms, mangroves and other intertidal plants and microorganisms. The emphasis is on new compounds (1425 in 416 papers for 2021), together with the relevant biological activities, source organisms and country of origin. Pertinent reviews, biosynthetic studies, first syntheses, and syntheses that led to the revision of structures or stereochemistries, have been included. An analysis of the number of authors, their affiliations, domestic and international collection locations, focus of MNP studies, citation metrics and journal choices is discussed.

MS/MS Molecular Networking Unveils the Chemical Diversity of Biscembranoid Derivatives, Neutrophilic Inflammatory Mediators from the Cultured Soft Coral Sarcophyton trocheliophorum

Biscembranoids are the distinctive tetraterpenoids owing a 14/6/14 membered tricyclic scaffold that have been mainly discovered in the soft corals, especially the genera Sarcophyton, Lobophytum and Sinularia. Recent findings have demonstrated the great anti-inflammatory potential of biscembranoid analogues in human neutrophils, motivating more chemical and biological explorations targeting these marine-derived natural products. In the current study, the chemical diversity of biscembranoids derived from the cultured-type Sarcophyton trocheliophorum von Marenzeller was illustrated through MS/MS molecular networking (MN) profiling approach. Based on the MN patterns, the prioritization of unknown biscembranoid derivatives was putatively analyzed. As a result, the biscembrane targeting isolation afforded two new metabolites, sarcotrochelides A (1) and B (2), along with six known analogues (3-8). Their structures and relative configurations were determined by spectroscopic methods. In vitro neutrophil inflammatory inhibition was further investigated for all isolates based on reduced superoxide anion (O₂^•-) generation detections. Compounds 5-8 showed significant dose-dependently inhibitory effects, suggesting the cruciality of 6,7-dihydrooxepin-2(5H)-one moiety and saturated γ-lactone ring in their reactive oxygen species (ROS)-dependent anti-inflammatory properties.

Lonicerae Japonicae Flos Attenuates Neutrophilic Inflammation by Inhibiting Oxidative Stress

Lonicerae japonicae flos (LJ) is an Asian traditional herb that is used as a dietary supplement, tea, and beverage to clear heat and quench thirst. However, no studies investigated its effect on activated human neutrophils, which played a crucial role in the bad prognosis of coronavirus disease of 2019 (COVID-19) patients by aggravating lung inflammation and respiratory failure. Herein, we evaluated the anti-inflammatory effect of LJ ethanol extract (LJEE) on human neutrophils activated by N-formyl-methionyl-leucyl-phenylalanine (fMLF). Our experimental results indicated that LJEE suppressed fMLF-activated superoxide anion (O₂^•−) generation, the expression of CD11b, and cell adhesion and migration, as well as the formation of neutrophil extracellular traps in human neutrophils. Further in-depth mechanical investigation revealed that pretreatment with LJEE accelerated the Ca²⁺ clearance, but did not affect the phosphorylation of mitogen-activated protein kinases (MAPKs) and protein kinase B (Akt) in activated human neutrophils. In addition, LJEE displayed a dose-dependent reactive oxygen species (ROS) scavenger activity, which assisted its anti-inflammatory activity. From the bioassay-coupled chromatographic profile, chlorogenic acids were found to dominate the anti-inflammatory effects of LJEE. Moreover, LJ water extract (LJWE) demonstrated an interrupting effect on the severe acute respiratory syndrome coronavirus-2 spike protein (SARS-CoV-2-Spike)/angiotensin-converting enzyme 2 (ACE2) binding. In conclusion, the obtained results not only supported the traditional use of LJ for heat-clearance, but also suggested its potential application in daily health care during the COVID-19 pandemic.

Bioactive Scalarane-Type Sesterterpenoids from Marine Sources

Scalarane-type sesterterpenoids have received considerable attention in the scientific literature due to their diverse carbon skeletons and various biological activities and pharmacological properties. Among all these derivatives are commonly isolated from marine sponges and are occasionally derived from shell-less mollusks, such as nudibranchs. This review comprehensively discusses the marine-derived natural sources that give rise to these scalarane-type sesterterpenoids, providing the names, their chemical structures, biological properties, with emphasis on anticancer activity and literature references related to these metabolites. A critical summary of the 221 compounds generated from January 2010 up to December 2021 for their potential as anticancer agents is presented.