Natural Products of Marine Origin for the Treatment of Colorectal and Pancreatic Cancers: Mechanisms and Potential

Sub-chronic oral toxicity study of the alkaloid rich fraction from Luffa cylindrica fruit in Sprague-Dawley rats

The loofah/sponge gourd Luffa cylindrica (L.), a member of the Cucurbitaceae family, is one of the neglected medicinal plants. Traditionally, Luffa cylindrica is prescribed for inducing labor. It has a long history of use in China for the treatment of fever, diabetes, dyspnea, and dysentery. This study investigated the toxicity profile of the alkaloid-rich fraction of Luffa cylindrica (ARF-LC) for the first time in Sprague Dawley rats. A total of 80 rats (40 male and 40 female rats) aged 13 weeks old and weighing 200-220 g were selected for this study. In SD rats, sub-chronic oral toxicity was investigated at doses of 100, 200, and 400 mg/kg/d for a total of 90 days, followed by a 30-day recovery period. The results showed no variation in body weight among the three dose groups compared to the control group. Treatment-related adverse events, such as alterations in hematology and serum biochemistry parameters and the histology of the liver were sporadic in the high-dose rats but within the reference range. However, these changes disappeared after the doses were withdrawn during the recovery period. In conclusion, the "no observed adverse effect level" (NOAEL) of oral administration of ARF-LC in SD rats was considered 400 mg/kg/d and can be studied for its potential in further in vivo chronic investigations.

Natural Products and Pharmacological Properties of Symbiotic Bacillota (Firmicutes) of Marine Macroalgae

The shift from the terrestrial to the marine environment to discover natural products has given rise to novel bioactive compounds, some of which have been approved for human medicine. However, the ocean, which makes up nearly three-quarters of the Earth's surface, contains macro- and microorganisms whose natural products are yet to be explored. Among these underexplored marine organisms are macroalgae and their symbiotic microbes, such as Bacillota, a phylum of mostly Gram-positive bacteria previously known as Firmicutes. Macroalgae-associated Bacillota often produce chemical compounds that protect them and their hosts from competitive and harmful rivals. Here, we summarised the natural products made by macroalgae-associated Bacillota and their pharmacological properties. We discovered that these Bacillota are efficient producers of novel biologically active molecules. However, only a few macroalgae had been investigated for chemical constituents of their Bacillota: nine brown, five red and one green algae. Thus, Bacillota, especially from the marine habitat, should be investigated for potential pharmaceutical leads. Moreover, additional diverse biological assays for the isolated molecules of macroalgae Bacillota should be implemented to expand their bioactivity profiles, as only antibacterial properties were tested for most compounds.

Antiproliferative, Antioxidant, Chemopreventive and Antiangiogenic Potential of Chromatographic Fractions from Anemonia sulcata with and without Its Symbiont Symbiodinium in Colorectal Cancer Therapy

Anemonia sulcata may be a source of marine natural products (MNPs) due to the antioxidant and antitumor activity of its crude homogenates shown in vitro in colon cancer cells. A bioguided chromatographic fractionation assay of crude Anemonia sulcata homogenates with and without its symbiont Symbiodinium was performed to characterize their bioactive composition and further determine their biological potential for the management of colorectal cancer (CRC). The 20% fractions retained the in vitro antioxidant activity previously reported for homogenates. As such, activation of antioxidant and detoxifying enzymes was also evaluated. The 40% fractions showed the greatest antiproliferative activity in T84 cells, synergistic effects with 5-fluoruracil and oxaliplatin, overexpression of apoptosis-related proteins, cytotoxicity on tumorspheres, and antiangiogenic activity. The predominantly polar lipids and toxins tentatively identified in the 20% and 40% fractions could be related to their biological activity in colon cancer cells although further characterizations of the active fractions are necessary to isolate and purify the bioactive compounds.

Marine-Inspired Drugs and Biomaterials in the Perspective of Pancreatic Cancer Therapies

Despite its low prevalence, pancreatic cancer (PC) is one of the deadliest, typically characterised as silent in early stages and with a dramatically poor prognosis when in its advanced stages, commonly associated with a high degree of metastasis. Many efforts have been made in pursuing innovative therapeutical approaches, from the search for new cytotoxic drugs and other bioactive compounds, to the development of more targeted approaches, including improved drug delivery devices. Marine biotechnology has been contributing to this quest by providing new chemical leads and materials originating from different organisms. In this review, marine biodiscovery for PC is addressed, particularly regarding marine invertebrates (namely sponges, molluscs, and bryozoans), seaweeds, fungi, and bacteria. In addition, the development of biomaterials based on marine-originating compounds, particularly chitosan, fucoidan, and alginate, for the production of advanced cancer therapies, is also discussed. The key role that drug delivery can play in new cancer treatments is highlighted, as therapeutical outcomes need to be improved to give further hope to patients.