During a 2013 cruise in the Southern Ocean we collected specimens of the octocoral Plumarella delicatissima between 800 and 950 m depth. Five new furanocembranoid diterpenes, keikipukalides A–E (1–5), the known diterpene pukalide aldehyde (6), and the known norditerpenoid ineleganolide (7) were isolated from the coral. These Plumarella terpenes lack mammalian cytotoxicity, while 2–7 display activity against Leishmania donovani between 1.9 and 12 μM. Structure elucidation was facilitated by one- and two-dimensional NMR spectroscopy and mass spectrometry, and keikipukalides A and E were confirmed by X-ray crystallography.

The Antarctic sponge Dendrilla antarctica is rich in defensive terpenoids with promising antimicrobial potential. Investigation of this demosponge has resulted in the generation of a small chemical library containing diterpenoid secondary metabolites with bioactivity in an infectious disease screening campaign focused on Leishmania donovani, Plasmodium falciparum, and methicillin-resistant Staphylococcus aureus (MRSA) biofilm. In total, eleven natural products were isolated, including three new compounds designated dendrillins B–D (10–12). Chemical modification of abundant natural products led to three semisynthetic derivatives (13–15), which were also screened. Several compounds showed potency against the leishmaniasis parasite, with the natural products tetrahydroaplysulphurin-1 (4) and dendrillin B (10), as well as the semisynthetic triol 15, displaying single-digit micromolar activity and low mammalian cytotoxicity. Triol 15 displayed the best profile against the liver-stage malaria parasites, while membranolide (5) and dendrillin C (11) were strong hits against MRSA biofilm cultures.

Purpose: Parasitic infections are a primary cause of illness worldwide and a public health problem. This study highlighted the prevalence of intestinal parasitic (IP) infections and their updated epidemiologic status from 2019 to 2023 at King Abdulaziz University Hospital, Jeddah, Saudi Arabia. Patients and Methods: A retrospective study was conducted from 2019 to 2023 at King Abdulaziz University Hospital. The laboratory results, socio-demographic information, and the year of data collection were collected from the hospital’s parasitology laboratory. The data were analyzed using SPSS version 26. Ethical approval was obtained from the National Committee of Bioethics (NCBE) - King Abdul Aziz City for Science and Technology, with an approval number of 258-22. Results: During the study period, 7673 stool samples were requested for intestinal parasite examination. The prevalence of IP infection from 2019 to 2023 was 212/7673, with a percentage of 2.8%. Infected patients had a mean (SD) age of 37.68 (17.27) years. Most infected patients were females (61%) and from Saudi Arabia (37.1%). Most stool samples were brown (79.1%), and about half were soft (51.7%). 2019 had the highest number of infected cases (28.3%), while the number of cases decreased in 2023 (8.8%), the lowest during five years. The most predominant parasite among study subjects was Blastocystis hominis (48.11%). Conclusion: The prevalence of IP infection is lower than in previous comparable surveys. Maintaining personal hygiene, conducting epidemiological surveillance, and enhancing environmental sanitation can prevent and control infections.

Chemical investigation of an Antarctic deep-water octocoral has led to the isolation of four new compounds, including three illudalane sesquiterpenoids (1–3) related to the alcyopterosins, a highly oxidized steroid, alcyosterone (5), and five known alcyopterosins (4, 6–9). The structures were established by extensive 1D and 2D NMR analyses, while 9 was verified by XRD. Alcyopterosins are unusual for their nitrate ester functionalization and have been characterized with cytotoxicity related to their DNA binding properties. Alcyopterosins V (3) and E (4) demonstrated single-digit micromolar activity against Clostridium difficile, an intestinal bacterium capable of causing severe diarrhea that is increasingly associated with drug resistance. Alcyosterone (5) and several alcyopterosins were similarly potent against the protist Leishmania donovani, the causative agent of leishmaniasis, a disfiguring disease that can be fatal if not treated. While the alcyopterosin family of sesquiterpenes is known for mild cytotoxicity, the observed activity against C. difficile and L. donovani is selective for the infectious agents.