ABSTRACT

Skin is a vital organ of the body; primarily composed of three layers continuously exposed to external environment. Exposure to pollution, chemicals, UV radiation etc. damages the epidermis leading to skin ageing. Skin ageing is a natural phenomena which, happens due to intrinsic or extrinsic factors. Since ancient times, people have used different herbs or plant extracts to combat ageing.  resveratrol, epicatechin, ellagic acid and apigenin are used in cosmetic formulations to combat skin ageing. These phytochemicals produced by plants reduce the physiological signs of ageing by reduction of ROS, protecting and stimulating matrix-associated proteins, absorption of UV rays, and maintaining the water-balance in the skin. This review highlights the anti-ageing phytochemicals for combating skin ageing influenced by external environment. 

INTRODUCTION
Skin is a protective barrier against the external environment.
Its function is to regulate temperature, fluid balance, to
protect from harmful microbes, and UV radiation in sunlight
(1). The skin is composed of three layers: epidermal, dermal,
and subcutaneous, out of which epidermis is adversely
affected by extrinsic factors. Ageing phenomena starts
from the moment we are born and is markedly visible on
the skin in progressive years. The inherent desire of people is
to live longer and look younger for a long period of time
(2). The modern science and technology provides plastic
surgery, laser rejuvenation, and many more invasive
techniques. Noninvasive techniques do not involve any risks
or complications and mostly free of side effects as
compared to the invasive techniques which is more painful
and laborious. Over the last decade, there has been an
increase in the use of herbal extracts or phytochemicals in
cosmetics to reduce the ageing process. Plants produce a
large number of secondary metabolites with simple to
complex structures such as terpenoids, alkaloids,
flavonoids, and phenolic compounds (3). People from
China, India and Egypt use plant powders and herbs to
look young and beautiful (4). The recent trends in anti-
ageing skin care products is focussed on developing new
plant extracts and botanical ingredients based on their
traditional medicinal uses (5, 6). The extracts of Aloe vera,
Amla, Turmeric, Triphala, and Gotukala are extensively
used in herbal cosmetic industries due to their skin
beneficial properties (7, 8, 9).
Skin ageing occurs due to two major factors, i.e. intrinsic
and extrinsic (10). Intrinsic skin ageing is a natural
physiological ageing process that involves the age-
dependent decline of cell, tissue function, and
degradation of fibre network in the skin. Extrinsic skin
ageing depends on external factors such as sun exposure,
exposure to UV rays, and environmental pollution. This
process is also known as photo ageing. Short wavelength
UVB penetrates deeper through the skin and damage the
dermis while UVA damage the epidermis of the skin. UV
radiation also stimulates ROS synthesis that is involved in
mutagenesis. Almost 90% of the skin changes occur due to
extrinsic factors (11). The importance of skin-ageing related
research is to understand the molecular processes that
cause ageing and develop the strategies to slow down
these processes. The major different types of cellular
damages that contribute to skin ageing are aggregations
of reactive oxygen species, photo ageing, accumulation of
a low-grade proinflammatory phenotype, reduction in age-
related autophagy, dehydration of skin, inhibition of
collagen and elastin synthesis (12,13). The beneficial effects
of dietary nutrients might also be important to reduce
health related and intrinsic ageing. This review focuses on
the extrinsic skin ageing in humans and their treatments by
plant-based bioactives
CONCLUSION
"Phytochemicals derived from plants have a lot of skin
beneficial properties related to UV protection, antioxidant
action, matrix protection and skin hydration. Over the past
decade, a lot of phytochemicals from the plant extracts have
been explored and their biological activities well-studied in
vitro. Therefore, there is a continuous requirement for more
clinical studies with emphasis on the concentration of the
ingredient in herbal products, their formulation, safety, and
the anti-ageing effect duration." 
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