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Ficus natalensis subsp. leprieurii also known as the natal fig is a fruit-producing tree belonging to the family Moraceae and widely distributed in African countries and cultivated in Egypt. F. natalensis is common with a myriad of traditional and medicinal importance. Owing to the increased demand for natural products with new structural compositions, the current study aimed to separate and elucidate the structure of triterpenoid saponins from F. natalensis leaves. Our previous biological investigation of F. natalensis leaves revealed its potent antioxidant and anti-inflammatory characteristics, and its ability to alleviate Cd-induced reproductive toxicity. Phytochemical investigation of F. natalensis leaves revealed the separation and structure elucidation of seven (1–7) compounds belonging to triterpenoid saponins using NMR and MS data and identified for the first time in F. natalensis. The isolated compounds were identified as 3-O-β-D-glucopyranosyl (1 → 4) β-D-glucopyranosyl (1 → 4)–α-L-rhamnopyranosyl-quinovic acid-28-O-β-D-glucopyranosyl (1 → 4)–α-L-rhamnopyranosyl (1 → 2)–α-L-arabinopyranoside ester (1), 3-O-β-D-glucopyranosyl (1 → 4) α-L rhamnopyranosyl-quinovic acid-28-O-β-D-glucopyranosyl (1 → 4)–α-L-rhamnopyranosyl (1 → 2) α-L-arabinopyranoside (2), 3-O-β-D-glucopyranosyl–quinovic acid-28-O-β-D-glucopyranosyl ester (3), as 3-O-α-L-rhamnopyranosyl-quinovic acid-28-O-β-D-glucopyranoside ester (4), 3-O-β-D-glucopyranosyl oleanolic acid (5), 3-methoxy-oleanolic acid-28-O-α-L-rhamnopyranoside (6), and 3-O-α-L-rhamnopyranosyl-oleanolic acid-28-O-β-D-glucopyranoside ester (7). Among the identified compounds, compounds 1 and 2 were identified for the first time in nature according to Reaxys and Web of Science database.

Saponins are amphiphilic molecules consisting of carbohydrate and either triterpenoid or steroid aglycone moieties and are noted for their multiple biological activities—Fungicidal, antimicrobial, antiviral, anti-inflammatory, anticancer, antioxidant and immunomodulatory effects have all been observed. Saponins from natural sources have long been used in herbal and traditional medicines; however, the isolation of complexed saponins from nature is difficult and laborious, due to the scarce amount and structure heterogeneity. Chemical synthesis is considered a powerful tool to expand the structural diversity of saponin, leading to the discovery of promising compounds. This review focuses on recent developments in the structure optimization and biological evaluation of synthetic triterpenoid and steroid saponin derivatives. By summarizing the structure–activity relationship (SAR) results, we hope to provide the direction for future development of saponin-based bioactive compounds.

Saponins are an important group found in Chenopodium quinoa. They represent an obstacle for the use of quinoa as food for humans and animal feeds because of their bitter taste and toxic effects, which necessitates their elimination. Several saponins elimination methods have been examined to leach the saponins from the quinoa seeds; the wet technique remains the most used at both laboratory and industrial levels. Dry methods (heat treatment, extrusion, roasting, or mechanical abrasion) and genetic methods have also been evaluated. The extraction of quinoa saponins can be carried out by several methods; conventional technologies such as maceration and Soxhlet are the most utilized methods. However, recent research has focused on technologies to improve the efficiency of extraction. At least 40 saponin structures from quinoa have been isolated in the past 30 years, the derived molecular entities essentially being phytolaccagenic, oleanolic and serjanic acids, hederagenin, 3β,23,30 trihydroxy olean-12-en-28-oic acid, 3β-hydroxy-27-oxo-olean-12en-28-oic acid, and 3β,23,30 trihydroxy olean-12-en-28-oic acid. These metabolites exhibit a wide range of biological activities, such as molluscicidal, antifungal, anti-inflammatory, hemolytic, and cytotoxic properties.

QS-21 is a potent vaccine adjuvant and remains the only saponin-based adjuvant that has been clinically approved for use in humans 1 , 2 . However, owing to the complex structure of QS-21, its availability is limited. Today, the supply depends on laborious extraction from the Chilean soapbark tree or on low-yielding total chemical synthesis 3 , 4 . Here we demonstrate the complete biosynthesis of QS-21 and its precursors, as well as structural derivatives, in engineered yeast strains. The successful biosynthesis in yeast requires fine-tuning of the host’s native pathway fluxes, as well as the functional and balanced expression of 38 heterologous enzymes. The required biosynthetic pathway spans seven enzyme families—a terpene synthase, P450s, nucleotide sugar synthases, glycosyltransferases, a coenzyme A ligase, acyl transferases and polyketide synthases—from six organisms, and mimics in yeast the subcellular compartmentalization of plants from the endoplasmic reticulum membrane to the cytosol. Finally, by taking advantage of the promiscuity of certain pathway enzymes, we produced structural analogues of QS-21 using this biosynthetic platform. This microbial production scheme will allow for the future establishment of a structure–activity relationship, and will thus enable the rational design of potent vaccine adjuvants. QS-21—an FDA-approved vaccine adjuvant—and several structural analogues of QS-21 can be synthesized in engineered yeast strains, and this process is much less laborious compared with the conventional mode of extraction from the Chilean soapbark tree.

•Q. brasiliensis saponins display less toxicity than commercially available saponins.•Q. brasiliensis AE and QB-80 saponins revealed molecular masses similar to Quil A®.•AE and QB-80 adjuvanted BVDV vaccines induce long term specific immune responses in mice.•AE formulations provide dose-sparing of BVDV antigen. Saponin-based adjuvants are promising adjuvants that enhance both humoral and T-cell-mediated immunity. One of the most used natural products as vaccine adjuvants are Quillaja saponaria bark saponins and its fraction named Quil A®. Despite that, its use has been restricted for human use due to safety issues. As an alternative, our group has been studying the congener species Quillaja brasiliensis saponins and its performance as vaccine adjuvants, which have shown to trigger humoral and cellular immune responses comparable to Quil A® but with milder side effects. Here, we studied a semi purified aqueous extract (AE) and a previously little characterized saponin-enriched fraction (QB-80) from Q. brasiliensis as vaccine adjuvants and an inactivated virus (bovine viral diarrhea virus, BVDV) antigen co-formulated in experimental vaccines in mice model. For the first time, we show the spectra pattern of the Q. brasiliensis saponins by MALDI-TOF, a novel and cost-effective method that could be used to characterize different batches during saponins production. Both AE and QB-80 exhibited noteworthy chemical similarities to Quil A®. In addition, the haemolytic activity and toxicity were assessed, showing that both AE and QB-80 were less toxic than Quil A®. When subcutaneously inoculated in mice, both fractions promoted long-term strong antibody responses encompassing specific IgG1 and IgG2a, enhanced the avidity of IgG antibodies, induced a robust DTH reaction and significantly increased IFN-ɣ production in T CD4+ and T CD8+ cells. Furthermore, we have proven herein that AE has the potential to promote dose-sparing, substantially reducing the dose of antigen required for the BVDV vaccines and still eliciting a mixed Th1/Th2 strong immune response. Based on these results, and considering that AE is a raw extract, easier and cheaper to produce than commercially available saponins, this product can be considered as candidate to be escalated from experimental to industrial uses.

Improved seasonal influenza vaccines for older adults that can induce broadly cross-reactive antibodies and enhanced T-cell responses, particularly against A H3N2 viruses, while avoiding egg-adaptive antigenic changes, are needed. We aimed to show that the Matrix-M-adjuvanted quadrivalent nanoparticle influenza vaccine (qNIV) was immunologically non-inferior to a licensed, standard-dose quadrivalent inactivated influenza vaccine (IIV4) in older adults. This was a phase 3 randomised, observer-blinded, active-comparator controlled trial done across 19 US community-based clinical research sites during the 2019–20 influenza season. Participants were clinically stable and community-dwelling, aged at least 65 years, and were randomised in a 1:1 ratio using an interactive web response system to receive a single intramuscular dose of qNIV or IIV4. The primary objective was to describe safety and show that qNIV was immunologically non-inferior to IIV4. The primary outcomes were adverse events by treatment group and comparative haemagglutination-inhibiting antibody responses (assayed with egg-propagated virus) on day 28, summarised in terms of the ratio of geometric mean titres (GMTRqNIV/IIV4) and seroconversion rate (SCR) difference between participants receiving qNIV or IIV4 for all four vaccine homologous influenza strains. The immunogenicity outcome was measured in the per-protocol population. Non-inferiority was shown if the lower bound of the two-sided 95% CI on the GMTRqNIV/IIV4 was at least 0·67 and the lower bound of the two-sided 95% CI on the SCR difference -was at least −10%. The study is registered with clinicaltrials.gov, NCT04120194, and is active and not recruiting. 2742 adults were assessed for eligibility and 2654 were enrolled and randomised between Oct 14, 2019, and Oct 25, 2019; 1333 participants were randomised to the qNIV group and 1319 to the IIV4 group (two participants withdrew consent before being assigned to a group). qNIV showed immunological non-inferiority to IIV4: GMTRqNIV/IIV4 for the four vaccine homologous influenza strains was A/Brisbane 1·09 (95% CI 1·03 to 1·15), A/Kansas 1·19 (1·11 to 1·27), B/Maryland 1·03 (0·99 to 1·07), and B/Phuket 1·23 (1·16 to 1·29); and SCR difference was A/Brisbane 5·0 (95% CI 1·9 to 8·1), A/Kansas 7·3 (3·6 to 11·1), B/Maryland 0·5 (−1·9 to 2·9), and B/Phuket 8·5 (5·0 to 11·9). 659 (49·4%) of 1333 of participants in the qNIV group and 551 (41·8%) of 1319 participants in the IIV4 group had at least one treatment-emergent adverse event. More solicited adverse events were reported by participants in the qNIV group (551 [41·3%] of 1333) than in the IIV4 group (420 [31·8%] of 1319), and were comprised primarily of mild to moderate transient injection site pain (341 [25·6%] in the qNIV group vs 212 [16·1%] in the IIV4 group). qNIV was well tolerated and produced qualitatively and quantitatively enhanced humoral and cellular immune response in older adults compared with IIV4. qNIV might enhance the effectiveness of seasonal influenza vaccination, and future studies to show clinical efficacy are planned. Novavax.

Plants continuously evolve new defense compounds. One class of such compounds is triterpenoid saponins. A few species in the Barbarea genus produce saponins as the only ones in the large crucifer family. However, the molecular mechanism behind saponin biosynthesis and their role in plant defense remains unclear. a We used pathway reconstitution in planta, enzymatic production of saponins in vitro, insect feeding assays, and bioinformatics to identify a missing gene involved in saponin biosynthesis and saponin-based herbivore defense. A tandem repeat of eight CYP72A cytochromes P450 colocalise with a quantitative trait locus (QTL) for saponin accumulation and flea beetle resistance in Barbarea vulgaris. We found that CYP72A552 oxidises oleanolic acid at position C-23 to hederagenin. In vitro-produced hederagenin monoglucosides reduced larval feeding by up to 90% and caused 75% larval mortality of the major crucifer pest diamondback moth and the tobacco hornworm. Sequence analysis indicated that CYP72A552 evolved through gene duplication andhas been under strong selection pressure. In conclusion, CYP72A552 has evolved to catalyse the formation of hederagenin-based saponins that mediate plant defense against herbivores. Our study highlights the evolution of chemical novelties by gene duplication and selection for enzyme innovations, and the importance of chemical modification in plant defense evolution.

•2 doses of HZ/su 2 months apart were immunogenic and efficacious against HZ.•We assessed humoral immunogenicity of 2 HZ/su doses given 6 or 12 months apart.•Humoral immunogenicity of the 0, 6-month schedule was non-inferior to the 0, 2-one.•Non-inferiority of the 0, 12- to the 0, 2-month schedule was not demonstrated.•No safety concerns were identified for any of the schedules. In phase III trials, 2 doses of a herpes zoster (HZ) subunit vaccine (HZ/su; 50 µg varicella-zoster virus glycoprotein E [gE] and AS01B Adjuvant System) administered 2-months apart in older adults (≥50 and ≥70 years) demonstrated >90% efficacy in preventing HZ and had a clinically acceptable safety profile. Here we report immunogenicity, reactogenicity and safety following administration of 2 HZ/su doses at intervals longer than 2 months. In this Phase III, open-label trial conducted in the US and Estonia, 354 adults ≥50 years were randomized 1:1:1 to receive 2 HZ/su doses 2, 6, or 12 months apart. gE-specific humoral immune responses were evaluated at pre-vaccination, 1 and 12 months post-dose 2. Co-primary objectives were to compare immune responses to HZ/su 1 month post-dose 2 when given 6-months or 12-months apart to those administered 2-months apart. For each participant, safety information was collected from dose 1 to 12 months post-dose 2. 346 participants completed the study and 343 were included in the according-to-protocol cohort for immunogenicity. One month post-dose 2, vaccine response rates were 96.5% (97.5% confidence interval [CI]: 90.4; 99.2) and 94.5% (97.5% CI: 87.6; 98.3) for the 0, 6- and 0, 12-month schedules, respectively, both schedules meeting the pre-defined criterion. Non-inferiority of anti-gE geometric mean concentrations was demonstrated for HZ/su administered on 0, 6-month compared to a 0, 2-month schedule; however, HZ/su administered on a 0, 12-month schedule did not meet the non-inferiority criterion. Injection site pain was the most commonly reported solicited adverse event (AE). 26 participants each reported at least 1 serious AE; none were assessed as related to vaccination. Immune responses to HZ/su administered at 0, 6-month were non-inferior to those elicited by a 0, 2-month schedule. HZ/su exhibited a clinically acceptable safety profile for all dosing intervals. Clinical Trials Registration: Clinicaltrials.gov (NCT01751165).

Summary Transient expression in Nicotiana benthamiana offers a powerful and versatile platform for rapid production of complex specialized metabolites. Steroidal glycoalkaloids (SGAs) and steroidal saponins produced by members of the Solanaceae family are known for their diverse structures and activities including antimicrobial, anticancer, antiviral, and anti‐inflammatory. Attempts to reconstitute their complete biosynthetic pathway have been unsuccessful to date. In this study, we identified a different tomato (Solanum lycopersicum) GLYCOALKALOID METABOLISM2 (SlGAME2‐NEW) enzyme as a xylosyltransferase in the penultimate step of α‐tomatine and dehydrotomatine biosynthesis. The discovery of SlGAME2‐NEW facilitated the engineering of tomato SGAs and steroidal saponin biosynthesis in N. benthamiana. Expressing from 9 to 15 genes in combination we efficiently engineered a total of 20 steroidal ‘end products’ (both alkaloids and saponins) typically produced by tomato and eggplant and ones merely found in wild tomato species. Furthermore, we engineered the biosynthetic pathway of the steroidal saponins uttroside B, dehydrouttroside B, and their stereoisomers [25(S)‐uttroside B and 25(S)‐dehydrouttroside B]. Production of these metabolites in N. benthamiana opens broad possibilities for examining and exploring their therapeutic potential. This study therefore makes a significant contribution to the application of synthetic biology for producing high‐value steroidal metabolites in heterologous plant hosts.

Saponaria sicula Raf. grows in Sicily, Sardinia, and Algeria on limestone cliffs and volcanic sands 1300–2500 m above sea level. The aim of the present study was to investigate how the pedo-climatic conditions influence the micromorphological, phytochemical, and biological properties of Sicilian S. sicula leaves collected in the Madonie Mountains (SsM) and on Etna Mt (SsE). Micromorphological investigations revealed that leaves from SsM had a higher amount of calcium oxalate druses in the mesophyll and a more intense blue–green staining with Toluidine blue O, indicating a higher content of polyphenols. These data were confirmed by phytochemical analyses carried out on hydroalcoholic extracts, which showed a higher content of total phenols (8.56 ± 0.57 g GAE/100 g DE) and flavonoids (6.09 ± 0.17 g RE/100 g DE) in SsM. Sixty-four compounds were identified by LC-DAD-ESI-MS analysis with propelargonidin dimer as the most abundant compound (10.49% and 10.19% in SsM and SsE, respectively). The higher polyphenol content of SsM leaves matches also with their biological activity, identifying SsM extract as the strongest plant complex (IC[sub.50] 2.75–477.30 µg/mL). In conclusion, the present study experimentally demonstrates that not only climatic differences but also soil characteristics affect the micromorphological, phytochemical, and biological features of this plant species.