The most successful research using adventitious roots for cosmetics ingredients is saikosaponin production by
root culture of B. falcatum L. The root of B. falcatum L, known as Bupleuri radix, is a galenical formulated in a variety
of TCMs. Among the more than 10 different saikosaponins, SSa and SSd are especially known as pharmacologically
active components, possessing properties such as antiallergic activity, analgesic action, and antiinflammatory
action. SSb1 and SSb2, which are produced artificially from SSa and SSd, have been recognized
as unique biologically active substances for skin cells, as described in Section 3.11.5. Kusakari et al.50 overcame
the defect of slower growth of adventitious roots by regulating lateral root differentiation. They found that the
formation of the lateral roots, which was induced in the presence of auxin (indolebutyric acid), was strongly suppressed as the sugar concentration was increased (Figure 32). This effect may be involved in the scavenging
effect of sugar on hydroxyl radical51 because lateral root initiation in B. falcatum root culture was promoted by
stresses such as drought or heat, and active oxygen species that the addition of hydrogen peroxide or methylviologen
contributed.52 As saikosaponin was accumulated only on lateral roots and original roots were losing their
function to root tissues during the culture in that culture system, the prompt increase of lateral root formation was
crucially important. However, as sucrose is also an energy source, a two-step culture was adopted, with the addition
of 1% sucrose at the beginning of the culture and 6%sucrose thereafter at 14 days when lateral roots had emerged.
This means adding sugar greatly improved the productivity, affording 0.8 g l1 of SSa and SSd. In addition, they
developed a new type of tank for commercial production (Figure 33) and have been producing the extract
containing SSb1 and SSb2, which were produced by converting SSa and SSd in the extract by regulating pH.
Saikosaponin-containing extract was compounded in a new brand of cosmetics called ‘Bioperformance’ by Shiseido
Co., Ltd., successfully marketed in Europe. Saikosaponin-containing extract has been used in cosmetics for more
than 10 years; this extract was the first repeat product manufactured by biotechnological means.