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Citrus Stem Cells

Also known as: Citrus stem cells, citrus plant stem cells, citrus fruit stem cells, Citrus sinensis extract, Citrus Stem Cells (Extract)

Overview

Citrus Stem Cells, often referred to as citrus plant stem cells or citrus fruit stem cells, are undifferentiated cells isolated from citrus plants, primarily from fruit or leaf tissues of species like *Citrus sinensis* (sweet orange). While the term 'stem cells' might suggest live, viable cells in supplements, these products typically contain extracts rich in bioactive compounds rather than living plant cells. These extracts are utilized in both cosmetic and nutraceutical supplements for their purported regenerative, antioxidant, and anti-inflammatory properties. They are rich in beneficial compounds such as flavonoids, antioxidants, and various secondary metabolites. Research indicates that the benefits attributed to 'Citrus Stem Cells' are largely mediated by the associated citrus flavonoids and other phytochemicals present in the extracts, which are known to promote cell protection against oxidative stress and support cellular function. The primary applications include skin care for anti-aging and hydration, and cardiovascular health due to the effects of citrus flavonoids on endothelial function. While substantial research exists on citrus flavonoids and fruit extracts, direct clinical evidence specifically on isolated citrus stem cells as a supplement ingredient is still emerging, with most evidence being indirect.

Benefits

The primary benefits of citrus stem cell extracts are largely attributed to their rich content of citrus flavonoids and other bioactive compounds. A meta-analysis of 8 randomized controlled trials (RCTs) involving 596 participants demonstrated that citrus flavonoid supplementation significantly improves endothelial function, as measured by flow-mediated vasodilation (FMD), with a pooled increase of 2.75% (95% CI: 1.29, 4.20; p < 0.001). This improvement is clinically relevant as endothelial dysfunction is a key marker for cardiovascular risk. A dose-response relationship was observed, with each 200 mg/day increment in citrus flavonoids increasing FMD by 1.09%. This suggests a strong, evidence-based benefit for cardiovascular health, particularly for individuals with endothelial dysfunction. Additionally, fruit extracts, including those derived from citrus, have been shown to reduce transepidermal water loss (TEWL), leading to improved skin barrier function and hydration (SMD = −6.54; 95% CI: −12.15, −0.92; p=0.02) in a meta-analysis of RCTs. This indicates a moderate level of evidence for skin health benefits, particularly for improving hydration and barrier integrity. Most RCTs supporting these benefits ranged from 8 to 12 weeks in duration, suggesting that consistent, medium-term supplementation is required to observe effects.

How it works

Citrus stem cell extracts primarily exert their effects through the bioactive compounds they contain, particularly citrus flavonoids. These compounds act as potent antioxidants, effectively reducing oxidative stress by scavenging reactive oxygen species (ROS). This antioxidant action is crucial in protecting cells and tissues from damage. Furthermore, citrus flavonoids enhance nitric oxide (NO) bioavailability by activating endothelial nitric oxide synthase (eNOS), an enzyme responsible for NO production. Increased NO levels lead to vasodilation, improving blood flow and endothelial function within the cardiovascular system. In the integumentary system, these extracts contribute to improved skin hydration and barrier function, likely through their antioxidant and anti-inflammatory properties, which help maintain skin integrity and reduce transepidermal water loss. The benefits are mediated by these phytochemicals rather than by live plant cells directly interacting with human cells.

Side effects

Citrus flavonoids and fruit extracts, which are the active components in 'Citrus Stem Cells' supplements, are generally regarded as safe with a low incidence of adverse effects in clinical trials. No common side effects (occurring in >5% of users) have been consistently reported in high-quality randomized controlled trials. Uncommon side effects (1-5% incidence) may include mild gastrointestinal discomfort, which has been occasionally reported with higher doses of flavonoid supplements. Rare side effects (less than 1% incidence) could include allergic reactions, though these are infrequent. Potential drug interactions exist, particularly with anticoagulants or antiplatelet drugs, due to the influence of flavonoids on blood clotting mechanisms; however, the clinical significance of these interactions is currently unclear. Contraindications include a known allergy to citrus fruits or related compounds. Data on the safety of citrus stem cell extracts in special populations such as pregnant or lactating women and children are limited, and caution is advised in these groups.

Dosage

For cardiovascular benefits, a minimum effective dose of citrus flavonoids, the primary active compounds in citrus stem cell extracts, is suggested to be around 200 mg per day, based on meta-analysis findings. Optimal dosage ranges may extend up to 400-600 mg per day, as higher doses have shown incremental benefits in improving endothelial function. The exact optimal dosing for 'citrus stem cell' extracts themselves, which are standardized for flavonoid content, is not yet firmly established. The maximum safe dose has not been clearly defined, but high doses of flavonoids are generally well tolerated. For observed effects, daily supplementation for at least 8 weeks is recommended. Oral supplements should be standardized for their flavonoid content. For skin benefits, topical formulations are also available. Absorption of citrus flavonoids can be enhanced when taken with food, and some flavonoids are metabolized by gut microbiota, contributing to their bioavailability. No specific cofactors are identified as required for their efficacy.

FAQs

Are citrus stem cells alive in supplements?

Typically, no. Supplements labeled 'citrus stem cells' contain extracts rich in bioactive compounds like flavonoids, not viable, living plant cells. The benefits come from these compounds.

Do citrus stem cells directly regenerate human cells?

There is no direct evidence that citrus stem cells or their extracts directly regenerate human cells. Their benefits are likely mediated by antioxidant and anti-inflammatory compounds.

Is citrus stem cell supplementation safe long-term?

Current evidence suggests that citrus flavonoid-rich extracts are safe for short to medium-term use. Long-term safety data specifically for 'citrus stem cell' extracts are limited.

Can citrus stem cells replace conventional treatments?

No, citrus stem cell extracts should not replace conventional medical treatments. They may serve as an adjunctive supplement for supporting cardiovascular or skin health.

Is topical application of citrus stem cell extracts effective for skin?

Yes, some evidence supports that fruit extracts, including those from citrus, can improve skin hydration and barrier function when applied topically, reducing transepidermal water loss.

Research Sources

https://pubmed.ncbi.nlm.nih.gov/38561995/ – This systematic review and dose-response meta-analysis of 8 RCTs (596 participants) found that citrus flavonoid supplementation significantly improved endothelial function (FMD increase of 2.75%). The study highlighted a clear dose-response relationship, indicating that citrus flavonoids are effective in enhancing cardiovascular health, though it noted moderate heterogeneity among studies.
https://pmc.ncbi.nlm.nih.gov/articles/PMC10436291/ – This meta-analysis of 3 RCTs (186 participants) investigated the effects of fruit extracts on skin aging. It concluded that fruit extracts, including citrus-derived ones, significantly reduce transepidermal water loss (TEWL), thereby improving skin barrier function and hydration. The study acknowledged high heterogeneity and a limited number of studies.