This comprehensive overview of the historical milestones in cell culture underscores key breakthroughs that have shaped the field over time. It begins with Wilhelm Roux’s seminal experiments in the 1880s, followed by the pioneering efforts of Ross Granville Harrison, who initiated groundbreaking experiments that fundamentally shaped the landscape of cell culture in the early 20th century. Carrel’s influential contributions, notably the immortalization of chicken heart cells, have marked a significant advancement in cell culture techniques. Subsequently, Johannes Holtfreter, Aron Moscona, and Joseph Leighton introduced methodological innovations in three-dimensional (3D) cell culture, initiated by Alexis Carrel, laying the groundwork for future consolidation and expansion of the use of 3D cell culture in different areas of biomedical sciences. The advent of induced pluripotent stem cells by Takahashi and Yamanaka in 2006 was revolutionary, enabling the reprogramming of differentiated cells into a pluripotent state. Since then, recent innovations have included spheroids, organoids, and organ-on-a-chip technologies, aiming to mimic the structure and function of tissues and organs in vitro, pushing the boundaries of biological modeling and disease understanding. In this review, we overview the history of cell culture shedding light on the main discoveries, pitfalls and hurdles that were overcome during the transition from 2D to 3D cell culture techniques. Finally, we discussed the future directions for cell culture research that may accelerate the development of more effective and personalized treatments.

Background: In several countries, the leaf juice of Agave sisalana (also known as sisal) is widely used topically, especially as an antiseptic, and orally for the treatment of different pathologies. However, in Brazil, which is the largest producer of Agave sisalana, its residue, which represents the majority of its weight, has been thrown away. For this reason, the determination of the pharmacological and toxicological potentials of sisal residue and its possible therapeutic use is seen as a way to contribute to the sustainable development and social promotion of the largest producer of sisal in Brazil, the interior of Bahia State, which is among the poorest areas in the country. Given the scarcity of available scientific studies on the pharmacological and toxicological properties of sisal residue juice, this study aimed to promote the acid hydrolysis of this juice to potentiate the anti-inflammatory effect already described in the literature. Furthermore, it aimed to evaluate the toxicological profile of the hydrolyzed extract (EAH) and to determine its acute toxicity, as well as its side effects on the reproductive aspects of rats. Method: The anti-inflammatory effect of EAH was evaluated in vitro using the induction of hemolysis by hypotonic solution and in vivo in rats using the carrageenan-induced paw edema test and the xylene-induced ear edema test. The acute toxicity, resulting from a single-dose administration, was investigated for some manifestation of toxic symptoms related to motor control and consciousness in rats. At a concentration of 100 mg/kg, by repeated doses, the reproductive toxicity effects of EAH in rats were assessed. Results: In vitro anti-inflammatory activity was positive using the human red blood cell membrane stabilization method. In both in vivo tests used to assess the anti-inflammatory activity, EAH (at three doses) significantly inhibited edema when compared to the control group. At a dose of 50 mg/kg, EAH exhibited a greater effect than indomethacin, a nonsteroidal anti-inflammatory drug with known activity. In vivo toxicological studies have shown that EAH does not present toxic effects when administered orally in a single dose, up to 1000 mg/kg. Finally, EAH promoted a gonadotoxic effect and increased the embryonic mortality rate after implantation. Conclusions: It is suggested that the anti-edematogenic effect of the acid hydrolysis extract from sisal juice is due to the high concentration of steroidal sapogenins. Therefore, this extract can be considered a potential new anti-inflammatory or even an important sapogenin source for the development of steroidal glucocorticoids. However, further studies are needed to elucidate the chemical composition of sisal juice. Regarding toxicology studies, EAH did not show cytotoxic and clastogenic potentials, but it presented a powerful reproductive toxic effect in rats.

Caryocar brasiliense Cambess is a plant species typical of the Cerrado, a Brazilian biome. The fruit of this species is popularly known as pequi, and its oil is used in traditional medicine. However, an important factor hindering the use of pequi oil is its low yield when extracted from the pulp of this fruit. Therefore, in this study, with aim of developing a new herbal medicine, we an-alyzed the toxicity and anti-inflammatory activity of an extract of pequi pulp residue (EPPR), fol-lowing the mechanical extraction of the oil from its pulp. For this purpose, EPPR was prepared and encapsulated in chitosan. The nanoparticles were analyzed, and the cytotoxicity of the encapsu-lated EPPR was evaluated in vitro. After confirming the cytotoxicity of the encapsulated EPPR, the following evaluations were performed with non-encapsulated EPPR: in vitro anti-inflammatory activity, quantification of cytokines, and acute toxicity in vivo. Once the anti-inflammatory activity and absence of toxicity of EPPR were verified, a gel formulation of EPPR was developed for topical use and analyzed for its in vivo anti-inflammatory potential, ocular toxicity, and previous stability assessment. EPPR and the gel containing EPPR showed effective anti-inflammatory activity and lack of toxicity. The formulation was stable. Thus, a new herbal medicine with anti-inflammatory activity can be developed from discarded pequi residue.

The primary source of hard fiber globally is Agave sisalana Perrine, also known as sisal. In areas where sisal is grown, the roots of the plant are usually left in the field after it has stopped producing, which leads to soil degradation and decreased sisal productivity. It is, therefore, critical to find alternatives to reuse this waste. This study explores the potential use of sisal waste in the cosmetic industry by incorporating a hydroethanolic extract (HER) into a cream–gel formulation, taking advantage of the plant’s recognized ethnopharmacological value. The study involves analyzing the extract’s phytochemical composition (flavonoids) and evaluating its cytotoxicity. Subsequently, the antioxidant and antiglycation activities of the extract and cream–gel are evaluated, as well as ex vivo ocular toxicity, photoprotective activity, and preliminary stability analyses. The HER extract showed a flavonoid composition (catechin, kaempferol, isorhamnetin, and chrysin) and maintained cell viability above 70% throughout all time points analyzed in the MTT assay. Furthermore, the extract and the formulation demonstrated proven antioxidant and antiglycation activities. The cream–gel’s UVB and UVA protection effectiveness with the HER was comparable to that of synthetic UVB/UVA sunscreens, with the samples proving nonirritating and stable. In conclusion, the extract has a significant presence of flavonoids, and the cream–gel developed with it did not present cytotoxicity and met the stability requirements, indicating phytocosmetic potential with antioxidant, antiglycation, and photoprotective properties.

Inflammation is a natural protective reaction of the body against endogenous and exogenous damage, such as tissue injuries, trauma, and infections. Thus, when the response is adequate, inflammation becomes a defense mechanism to repair damaged tissue, whereas when the response is inadequate and persistent, the increase in inflammatory cells, cytosines, and chymosins impair tissue regeneration and promote a response harmful to the organism. One example is chronic tissue inflammation, in which a simple lesion can progress to ulcers and even necrosis. In this situation, the anti-inflammatory medications available in therapy are not always effective. For this reason, the search for new treatments, developed from medicinal plants, has increased. In this direction, the plants Agave sisalana (sisal) and Punica granatum (pomegranate) are rich in saponins, which are secondary metabolites known for their therapeutic properties, including anti-inflammatory effects. Although Brazil is the world’s leading sisal producer, approximately 95% of the leaves are discarded after fiber extraction. Similarly, pomegranate peel waste is abundant in Brazil. To address the need for safe and effective anti-inflammatory treatments, this study aimed to create a topical mucoadhesive gel containing a combination of sisal (RS) and pomegranate residue (PR) extracts. In vitro experiments examined isolated and combined extracts, as well as the resulting formulation, focusing on (1) a phytochemical analysis (total saponin content); (2) cytotoxicity (MTT assay); and (3) a pharmacological assessment of anti-inflammatory activity (phagocytosis, macrophage spreading, and membrane stability). The results revealed saponin concentrations in grams per 100 g of dry extract as follows: SR—29.91 ± 0.33, PR—15.83 ± 0.93, association (A)—22.99 ± 0.01, base gel (G1)—0.00 ± 0.00, and association gel (G2)—0.52 ± 0.05. In MTT tests for isolated extracts, cytotoxicity values (µg/mL) were 3757.00 for SR and 2064.91 for PR. Conversely, A and G2 exhibited no cytotoxicity, with increased cell viability over time. All three anti-inflammatory tests confirmed the presence of this activity in SR, PR, and A. Notably, G2 demonstrated an anti-inflammatory effect comparable to dexamethasone. In conclusion, the gel containing SR and PR (i.e., A) holds promise as a novel herbal anti-inflammatory treatment. Its development could yield economic, social, and environmental benefits by utilizing discarded materials in Brazil.

This comprehensive overview of the historical milestones in cell culture underscores key breakthroughs that have shaped the field over time. It begins with Wilhelm Roux's seminal experiments in the 1880s, followed by the pioneering efforts of Ross Granville Harrison, who initiated groundbreaking experiments that fundamentally shaped the landscape of cell culture in the early 20th century. Carrel's influential contributions, notably the immortalization of chicken heart cells, mark a significant advancement in cell culture techniques. Holtfreter, Moscona, and Leighton introduced innovations such as 3D cell culture, laying the groundwork for further exploration. The advent of induced pluripotent stem cells by Takahashi and Yamanaka in 2006 was revolutionary, enabling the reprogramming of differentiated cells into a pluripotent state. Since then, recent innovations include spheroids, organoids, and organ-on-a-chip technologies, aiming to mimic the structure and function of tissues and organs in vitro, pushing the boundaries of biological modeling and disease understanding. In this review, we overview the history of cell culture shedding light on the main discoveries, pitfalls and hurdles that were overcome during the transition from 2D to 3D cell culture techniques. Finally, we discussed the future directions for cell culture research that may accelerate the development of more effective and personalized treatments.