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Antiviral Activity of Seaweeds and their Extracts
Published in Leonel Pereira, Therapeutic and Nutritional Uses of Algae, 2018
A potent HIV-inactivating protein, griffithsin, was isolated from the red alga Griffithsia sp. (see Table 5.1). Griffithsin is a new type of lectin that displays potent antiviral activity against laboratory strains and primary isolates of HIV-1 (IC50 = 0.043-0.63 nM) (Mori et al. 2005). This activity requires binding to viral glycoproteins (e.g., gp120, gp41 and gp160) in a monosaccharide-dependent manner (YasuharaBell and Lu 2010).
The vital role of animal, marine, and microbial natural products against COVID-19
Published in Pharmaceutical Biology, 2022
Aljawharah A. Alqathama, Rizwan Ahmad, Ruba B. Alsaedi, Raghad A. Alghamdi, Ekram H. Abkar, Rola H. Alrehaly, Ashraf N. Abdalla
Several natural compounds have been shown to interfere with viral attachment through the interaction between hACE2 and the S protein. A lectin isolated from the red alga Griffithsia sp. (Wrangeliaceae), griffithsin, has demonstrated broad anti-viral activity. It significantly inhibits SARS-CoV-2 infection in a dose-dependent manner in a SARS-CoV-2 pseudovirus infection assay with the half maximal inhibitory concentration (IC50) = 293 nmol/L. The anti-viral activity against live SARS-CoV-2 infection was confirmed by immunofluorescence and qRT-PCR assay, with activity (IC50 = 3 nmol/L) that was eleven times stronger than that of one of the potent anti-virals for COVID-19, remdesivir. More specifically, it inhibited SARS-CoV-2 viral adhesion in vitro through S-mediated cell–cell fusion and S1 subunit and RBD with an IC50 of 323 nmol/L by targeting the glycosylation sites in S1 subunit (Cai et al. 2020). The fungal decalactone dictyosphaeric acid A, obtained from the green alga Dictyosphaeria versluyii (Weber-van Bosse, Siphonocladaceae), has shown its inhibitory properties against disrupt TMPRSS2-S PPIs, a host protein that facilitates viral entry, and hACE2-S (Rahman et al. 2020; Senapati et al. 2021).
Vaginal multipurpose prevention technologies: promising approaches for enhancing women’s sexual and reproductive health
Published in Expert Opinion on Drug Delivery, 2020
Trinette Fernandes, Krishna Baxi, Sujata Sawarkar, Bruno Sarmento, José das Neves
One interesting method to incorporate multiple drugs, particularly incompatible ones, into a vaginal tablet is by formulating multi-layered tablets. For example, McConville and colleagues developed a multi-layered vaginal tablet for the delivery of dapivirine, acyclovir, and levonorgestrel [97]. The formulation was aimed at preventing HIV-1 and HSV-2 transmission, as well as providing contraception. In this study, the layers were designed for sustained or immediate drug release according to the desired release profile (Figure 1). The formulation was engineered in order to combine the immediate release of dapivirine (for initial protection from HIV-1) and up to 8 h maintenance of the same drug levels. The release was immediate for acyclovir and levonorgestrel [97]. In another study, Lal and colleagues developed fast-dissolving vaginal tablets/inserts for the delivery of griffithsin and carrageenan (Figure 2) [98]. Both actives are marine-derived carbohydrates with a broad range of reported antiviral activity. For instance, their combination showed to be more effective in reducing HPV transmission in mice as compared to single treatment with either compounds [99]. Fast-dissolving vaginal tablets/inserts composed of these active agents featured disintegration time within 1 min and formed a viscous bioadhesive gel that could provide wide coverage of the entire vaginal mucosa, thus potentially allowing rapid protection from viral infection [98].
An overview of the recent progress in Middle East Respiratory Syndrome Coronavirus (MERS-CoV) drug discovery
Published in Expert Opinion on Drug Discovery, 2023
Griffithsin, a protein isolated from the red alga Griffithsia, could be regarded as a promising MERS-CoV replication suppressor. Griffithsin attached to the glycans on the viral S protein through its three carbohydrate-binding motifs, and thus it could prevent viruses from attaching to host cells [134,135]. By eliminating glycans, griffithsin made the surface of the virus more accessible to the immune system of the host, which enabled the immune system to access the viral proteins [136]. Three medicinal plants, Azadirachta indica, Artemisia judaica, and Sophora tomentosa, were tested for their effectiveness against MERS-CoV [137]. S. tomentosa was effective against MERS-CoV with an IC50 value of 3.11 µg/ml.